Nitrogen-containing polysiloxane flame retardant as well as synthesis method and application thereof
By polymerizing nitrogen with siloxane to form a copolymer, the problems of low flame retardant efficiency, environmental unfriendliness, and poor compatibility of existing flame retardants are solved, achieving a highly efficient and environmentally friendly flame retardant effect while maintaining the mechanical properties of the material.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-10
- Publication Date
- 2026-04-10
AI Technical Summary
Existing flame retardants have problems such as low flame retardant efficiency, harm to the environment and human body, and impact on the performance of matrix materials. In particular, halogenated flame retardants release toxic gases, inorganic flame retardants have a large amount of additives that affect mechanical properties, and organic flame retardants have poor compatibility with the matrix.
By polymerizing nitrogen with siloxane to form a copolymer, the synergistic flame-retardant effect of N and Si on the same molecular chain is achieved. A nitrogen-containing polysiloxane flame retardant is then combined with diethyl aluminum hypophosphite to form a highly efficient and environmentally friendly flame retardant.
It achieves high-efficiency flame retardancy, halogen-free, low smoke, and low toxicity, while having little impact on the mechanical properties of the matrix material and strong heat resistance and moisture resistance.
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Figure CN121824595A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of flame-retardant materials, and particularly relates to a nitrogen-containing polysiloxane flame retardant as well as a synthesis method and application thereof. BACKGROUND
[0002] The extensive application of polymer materials makes the flame-retardant safety of the polymer materials a key requirement. Although traditional halogen-based flame retardants are highly efficient, they generate toxic, corrosive gases and smoke dust during combustion. Therefore, developing halogen-free flame retardants that are highly efficient, low-toxic, low-smoke and environmentally friendly has become an industry consensus and a main research direction.
[0003] Among the numerous halogen-free systems, organic silicon flame retardants can form a solid and stable inorganic ceramic protective layer containing Si-O bonds at high temperatures, effectively insulating oxygen and heat, and promoting the carbonization of the base material, thereby achieving excellent flame-retardant, smoke-suppressing and anti-dripping effects. The core advantage is environmental friendliness and the ability to maintain the mechanical properties of the base material.
[0004] Currently commonly used flame retardants mainly include halogen-based flame retardants, inorganic flame retardants (such as aluminum hydroxide and magnesium hydroxide), nitrogen-based flame retardants, nitrogen-based flame retardants and silicon-based flame retardants. However, the existing flame retardants have the following problems: (1) halogen-based flame retardants: high flame-retardant efficiency, but release toxic gases (such as hydrogen halide and dioxin) during combustion, which are harmful to the human body and the environment; (2) inorganic flame retardants: large addition amount (usually > 60 parts), which seriously affects the mechanical properties and processing properties of the base material; (3) organic flame retardants (such as nitrogen-based and nitrogen-based): limited flame-retardant effect when used alone, and poor compatibility with the base material; (4) silicone rubber itself is flammable (LOI ≈ 20.8%), and needs to be flame-retardant modified, but the existing flame retardants easily lead to a decrease in the mechanical properties.
[0005] Therefore, developing a flame retardant that is highly efficient, environmentally friendly, has good compatibility with the base material and has little effect on the mechanical properties has become a research focus. SUMMARY
[0006] The purpose of the present application is to provide a nitrogen-containing polysiloxane flame retardant as well as a synthesis method and application thereof. In the present application, nitrogen elements are chemically bonded to siloxane polymers to form copolymers, achieving the synergistic flame-retardant effect of N and Si on the same molecular chain, and solving the problems of composition compounding difficulty and uneven dispersion caused by the physical mixing of nitrogen compounds and siloxane into nylon.
[0007] The present application is implemented by the following technical solutions:
[0008] The present application protects a nitrogen-containing polysiloxane flame retardant, the structural formula of which is shown as formula (I): Formula (I); wherein R1 is selected from , , or n = 4~6.
[0009] This invention also protects a method for synthesizing the nitrogen-containing polysiloxane flame retardant, comprising the following steps:
[0010] In a reaction vessel, under nitrogen protection, isocyanate and solvent are added, and the temperature is gradually raised to 45℃~55℃. Then, a diamine compound is slowly added. After the addition is complete, the reaction is maintained at this temperature for 2~3 hours. Then, the temperature is gradually raised to 95℃~105℃ and the reaction is continued for 4~5 hours. The alcohol and water generated in the reaction are separated under reduced pressure. Then, the temperature is raised to 145℃~155℃ and the reaction is continued for 3~5 hours until no alcohol and water are separated. The reaction is then stopped to obtain the target product, nitrogen-containing polysiloxane flame retardant.
[0011] The reaction equation for this flame retardant is shown in equation (II) below: Formula (II)
[0012] Preferably, the isocyanate is 3-isocyanatopropyltrimethoxysilane.
[0013] Preferably, the diamine compound is selected from p-phenylenediamine, melamine, 4,4'-diaminodiphenylmethane and 4,4'-diaminodiphenyl sulfone, and the molar ratio of isocyanate to diamine compound is 2.1 to 2.5:1.
[0014] Further preferred, the molar ratio of isocyanate to diamine compound is 2.1~2.2:1.
[0015] Preferably, the solvent is selected from xylene, tetrahydrofuran, and toluene. The solvent in the solution of the diamine compound is the same as the reaction solvent, and the molar concentration of the solution of the diamine compound is 0.1~2.0 mol / L.
[0016] The molar concentration of the solution obtained by adding isocyanate to the solvent is 0.005~0.020 mol / L. More preferably, the molar concentration of the solution obtained by adding isocyanate to the solvent is 0.0067 mol / L.
[0017] This invention also protects the use of the nitrogen-containing polysiloxane flame retardant as a flame retardant additive in the preparation of composite flame retardants.
[0018] A composite flame retardant comprising the aforementioned nitrogen-containing polysiloxane flame retardant and aluminum diethylphosphite (ADP).
[0019] Preferably, the mass ratio of the nitrogen-containing polysiloxane flame retardant to diethyl aluminum hypophosphite is 1:5~6.
[0020] Further preferably, the mass ratio of the nitrogen-containing polysiloxane flame retardant to diethyl aluminum hypophosphite is 1:5.67.
[0021] This invention also protects a glass fiber reinforced nylon material comprising the aforementioned composite flame retardant, PA66, glass fiber, and additives.
[0022] Preferably, the mass ratio of the composite flame retardant, PA66, glass fiber, and additives is 28:111:60:1. The additives include lubricants and antioxidants.
[0023] Compared with the prior art, the beneficial effects of the present invention are: the flame retardant proposed in the present invention polymerizes nitrogen element with siloxane in the form of chemical bonding to form a copolymer, realizing the synergistic flame retardant effect of N and Si on the same molecular chain. At the same time, the flame retardant has good heat resistance, strong moisture resistance and high flame retardant efficiency. Detailed Implementation
[0024] The present invention will be further described in detail below with reference to the embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions in the art or as recommended by the manufacturer; the raw materials and reagents used, unless otherwise specified, are considered to be commercially available materials and reagents that can be obtained through conventional markets and other commercial channels. Example 1
[0025]
[0026] In a three-necked reaction flask equipped with a stirrer, reflux condenser, and thermometer, under nitrogen protection, 2.1 mmol of 3-isocyanatopropyltrimethoxysilane and 150 mL of xylene were added. The temperature was gradually raised to 50 °C, and then 10 mL of a xylene solution containing 1 mmol of p-phenylenediamine was slowly added dropwise. After the addition was complete, the reaction was maintained at this temperature for 3 hours. The temperature was gradually raised to 100 °C, and the alcohol and water byproducts were separated under reduced pressure. The reaction was continued for 4 hours, and then the temperature was raised to 150 °C and the reaction was continued for 3–5 hours until no alcohol was separated. The reaction was then stopped to obtain the target product. 1H NMR (500 MHz, Chloroform-d) δ 7.63– 7.56 (m, 45H), 6.86-6.82 (m, 15H), 6.25 (s, 7H), 5.45 (s, 20H), 4.94 (s,5H), 3.16-3.11 (m, 30H), 1.66 (s, 30H), 1.38-1.36 (m, 5H), 1.17 (t, J = 10.2Hz, 5H), 0.83 (t, J = 9.5 Hz, 20H). 13 C NMR (125 MHz, Chloroform-d) δ 156.47,134.28, 121.10, 43.59, 43.57, 43.39, 30.75, 28.62, 26.11, 23.27, 23.03,19.74. LC-MS[M+1] + =2499.5. Example 2
[0027]
[0028] In a three-necked reaction flask equipped with a stirrer, reflux condenser, and thermometer, 2.2 mmol of 3-isocyanatopropyltrimethoxysilane and 150 mL of xylene were added under nitrogen protection, and the temperature was gradually raised to 50°C. Melamine (1 mmol) was then slowly added dropwise, and the reaction was continued at this temperature for 2 hours. The temperature was gradually increased to 100°C, and the alcohol and water byproducts were separated under reduced pressure. The reaction was continued for 4 hours, then the temperature was raised to 150°C and the reaction continued for 3–5 hours until no more alcohol was separated. The reaction was then stopped to obtain the target product. 1 H NMR (500 MHz, Chloroform-d) δ 8.96 (s, 12H), 7.05-7.01 (m, 12H), 6.35 (s, 12H), 6.26 (s, 6H), 5.45 (s, 20H), 3.16-3.13 (m, 24H), 1.65 (s, 24H), 1.17 (t, J = 10.3 Hz, 4H), 0.83 (t, J = 9.5 Hz, 20H). 13 CNMR (125 MHz, Chloroform-d) δ 168.41, 160.13, 155.17, 43.63, 43.59, 30.70,26.07, 23.06, 19.73.LC-MS[M+1] +=2623.5. Example 3
[0029]
[0030] In a three-necked reaction flask equipped with a stirrer, reflux condenser, and thermometer, 3-isocyanatopropyltrimethoxysilane (2.1 mmol) and xylene (150 mL) were added under nitrogen protection, and the temperature was gradually raised to 50°C. Then, 4,4'-diaminodiphenyl sulfone (1 mmol) was slowly added dropwise, and the reaction was continued at this temperature for 3 hours. The temperature was gradually increased to 100°C, and the alcohol and water byproducts were separated under reduced pressure. The reaction was continued for 5 hours, and then the temperature was raised to 150°C and the reaction was continued for 3-5 hours until no alcohol was separated. The reaction was then stopped to obtain the target product. 1 H NMR (500 MHz, Chloroform-d) δ 7.89 – 7.83(m, 16H), 7.66 (s, 8H), 7.61 – 7.55 (m, 16H), 6.85-6.82 (m, 8H), 6.26 (s,6H), 5.45 (s, 12H), 3.15-3.13 (m, 16H), 1.65 (s, 16H), 1.17 (t, J = 10.3 Hz, 4H), 0.83 (t, J = 9.4 Hz, 12H). 13 C NMR (125 MHz, Chloroform-d) δ 156.47,143.76, 135.77, 128.96, 119.77, 43.58, 30.75, 26.11, 23.03, 19.74. LC-MS[M+1] + =2243.6. Example 4
[0031]
[0032] In a three-necked reaction flask equipped with a stirrer, reflux condenser, and thermometer, 2.2 mmol of 3-isocyanatopropyltrimethoxysilane and 150 mL of xylene were added under nitrogen protection, and the temperature was gradually raised to 50°C. Then, 1 mmol of 4,4'-diaminodiphenylmethane was slowly added dropwise, and the reaction was continued at this temperature for 3 hours. The temperature was gradually increased to 100°C, and the alcohol and water byproducts were separated under reduced pressure. The reaction was continued for 5 hours, then the temperature was raised to 150°C and the reaction was continued for 3–5 hours until no alcohol was separated. The reaction was then stopped to obtain the target product. 1H NMR (500 MHz, Chloroform-d) δ 7.56 –7.48 (m, 30H), 7.14 – 7.09 (m, 20H), 6.85-6.82 (m, 10H), 6.25 (s, 6H), 5.45(s, 16H), 3.86-3.83 (m, 10H), 3.16-3.11 (m, 20H), 1.65 (s, 20H), 1.17 (t, J =10.2 Hz, 4H), 0.83 (t, J = 9.5 Hz, 16H). 13 C NMR (125 MHz, Chloroform-d) δ156.47, 139.14, 135.31, 130.28, 119.96, 43.59, 43.57, 42.27, 30.75, 26.11, 23.03, 19.74. LC-MS[M+1] + =2550.6. Application Example 1
[0033] A composite flame retardant is obtained by adding the nitrogen-containing polysiloxane flame retardant of Example 1 and aluminum diethyl phosphite (ADP) into a high-speed mixer at the following mass percentages, and mixing for 5 minutes to obtain a high-temperature resistant, non-exudative, high-impact composite flame retardant for glass fiber reinforced nylon.
[0034] 15% nitrogen-containing polysiloxane flame retardant
[0035] Aluminum diethylphosphite (ADP) 85%. Application Example 2
[0036] A composite flame retardant is obtained by adding the nitrogen-containing polysiloxane flame retardant of Example 2 and aluminum diethylphosphite (ADP) into a high-speed mixer at the following mass percentages and mixing for 5 minutes to obtain a high-temperature resistant, non-precipitating, high-impact composite flame retardant for polyolefins.
[0037] 15% nitrogen-containing polysiloxane flame retardant
[0038] Aluminum diethylphosphite (ADP) 85%. Application Example 3
[0039] A composite flame retardant is obtained by adding the nitrogen-containing polysiloxane flame retardant of Example 3 and aluminum diethyl phosphite (ADP) into a high-speed mixer at the following mass percentages and mixing for 5 minutes to obtain a high-temperature resistant, non-exudative, high-impact composite flame retardant for glass fiber reinforced nylon.
[0040] 15% nitrogen-containing polysiloxane flame retardant
[0041] Aluminum diethylphosphite (ADP) 85%. Application Example 4
[0042] A composite flame retardant is obtained by adding the nitrogen-containing polysiloxane flame retardant of Example 4 and aluminum diethyl phosphite (ADP) into a high-speed mixer at the following mass percentages and mixing for 5 minutes to obtain a high-temperature resistant, non-precipitating, high-impact composite flame retardant for polyolefins.
[0043] 15% nitrogen-containing polysiloxane flame retardant
[0044] Aluminum diethylphosphite (ADP) 85%. Comparative Example 1
[0045] A composite flame retardant is obtained by adding melamine polyphosphate and aluminum diethyl phosphite (ADP) in the following mass percentages into a high-speed mixer and mixing for 5 minutes.
[0046] 15% melamine polyphosphate
[0047] Aluminum diethylphosphite (ADP) 85%. Comparative Example 2
[0048] A composite flame retardant is obtained by adding aluminum phosphite and aluminum diethylphosphite (ADP) in the following mass percentages into a high-speed mixer and mixing for 5 minutes.
[0049] 15% aluminum phosphite
[0050] Aluminum diethylphosphite (ADP) 85%.
[0051] The composite flame retardants prepared in Application Examples 1-4 and Comparative Examples 1-2 were added to glass fiber reinforced nylon (PA66) to prepare specimens. The specific methods are as follows: 420 g of composite flame retardant, 1665 g of PA66 (EP158, Huafeng), 900 g of glass fiber (short glass fiber, Jushi), 9 g of lubricant (Licowax E wax, Clariant), and 6 g of antioxidant (1098, BASF) were weighed and mixed evenly using a high-speed mixer; extrusion granulation was performed using a twin-screw extruder; and specimens were prepared using an injection molding machine. The flame retardant specimens were 125 mm long, 13.0 mm wide, and 1.6 mm thick; the impact specimens were 100 mm long, 8.0 mm wide, and 4.0 mm thick; and the exudation and temperature resistance specimens were 40 mm long, 30 mm wide, and 2.0 mm thick.
[0052] To test the precipitation resistance of the above specimens, the specific test method is to place the specimens in a constant temperature and humidity chamber at 85℃ and 85% humidity for 1000 hours and observe whether powder or crystals precipitate on the surface of the specimens.
[0053] The temperature resistance of the above specimens was tested by adjusting the injection temperature to 290℃, storing the material for 3 minutes, and comparing the color of the specimens before and after the storage period.
[0054] The tests were conducted according to the UL-94 vertical burning test standard, cantilever beam impact test standard, constant temperature and humidity exudation test standard, and temperature resistance test method. The results are shown in Table 1.
[0055] Table 1
[0056] Table 1 shows that the flame-retardant materials prepared in Examples 1-4 all achieved a flame-retardant rating of V0, significantly better than the V1 rating of Comparative Examples 1-2. The impact strength, exudation resistance, and temperature resistance of the flame-retardant materials prepared in Examples 1-4 were also significantly better than those in Comparative Examples 1-2. This indicates that the nitrogen-containing polysiloxane flame retardant proposed in this invention, when used as a synergist, enhances the flame-retardant performance, impact resistance, exudation resistance, and high-temperature resistance of the synergistic diethylaluminum hypophosphite composite flame retardant compared to other synergistic diethylaluminum hypophosphite composite flame retardants.
[0057] The above description of the embodiments is only for the purpose of helping to understand the technical solution and core idea of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.
Claims
1. A nitrogen-containing polysiloxane flame retardant, characterized in that, The structural formula is shown in equation (I): Equation (I); Where: R1 is selected from , , or n = 4~6.
2. The method for synthesizing the nitrogen-containing polysiloxane flame retardant according to claim 1, characterized in that, The process includes the following steps: In a reaction vessel, under nitrogen protection, isocyanate and solvent are added, and the temperature is gradually raised to 45℃~55℃. Then, a diamine compound is slowly added. After the addition is complete, the reaction is maintained at this temperature for 2~3 hours. The temperature is then gradually raised to 95℃~105℃ and the reaction is continued for 4~5 hours. The alcohol and water generated in the reaction are separated under reduced pressure. The temperature is then raised to 145℃~155℃ and the reaction is continued for 3~5 hours until no alcohol and water are separated. The reaction is then stopped to obtain the target product, a nitrogen-containing polysiloxane flame retardant.
3. The synthesis method according to claim 2, characterized in that, The isocyanate is 3-isocyanatopropyltrimethoxysilane.
4. The synthesis method according to claim 2 or 3, characterized in that, The diamine compound is selected from p-phenylenediamine, melamine, 4,4'-diaminodiphenylmethane and 4,4'-diaminodiphenyl sulfone, and the molar ratio of isocyanate to diamine compound is 2.1~2.5:
1.
5. The synthesis method according to claim 2 or 3, characterized in that, The solvent is selected from xylene, tetrahydrofuran, and toluene.
6. The application of the nitrogen-containing polysiloxane flame retardant according to claim 1 as a flame retardant additive in the preparation of composite flame retardants.
7. A composite flame retardant, characterized in that, It includes the nitrogen-containing polysiloxane flame retardant as described in claim 1 and diethyl aluminum hypophosphite.
8. The composite flame retardant according to claim 7, characterized in that, The mass ratio of the nitrogen-containing polysiloxane flame retardant to diethyl aluminum hypophosphite is 1:5~6.
9. A glass fiber reinforced nylon material, characterized in that, It includes the composite flame retardant as described in claim 7 or 8, PA66, glass fiber, and additives.
10. The glass fiber reinforced nylon material according to claim 9, characterized in that, The mass ratio of the composite flame retardant, PA66, glass fiber and additives is 28:111:60:1.