Low viscosity nitrogen-based modified flame-retardant smoke-suppressing silicone oil and preparation method thereof
Low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil was prepared by ring-opening addition reaction of terminal epoxy silicone oil and methylurea. This solved the problem of poor flame-retardant performance of epoxy silicone oil and improved flame-retardant and smoke-suppressing performance and thermal stability without affecting fluidity. It is suitable for polymer material modification and composite systems.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HEFEI UNIV OF TECH
- Filing Date
- 2026-04-20
- Publication Date
- 2026-06-09
AI Technical Summary
Existing epoxy silicone oils have poor flame retardant properties, produce a large amount of smoke and toxic gases when burning, and chemical modification methods have problems such as insufficient fluidity, increased viscosity, high cost, and flame retardant groups that can reduce the reactivity of epoxy.
A low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil was prepared by introducing nitrogen-containing groups through a ring-opening addition reaction between terminal epoxy silicone oil and methylurea. Catalysts such as 2,4,6-tris(dimethylaminomethyl)phenol and triethylamine were used, and the reaction conditions were controlled at 130-150℃ for 4-6 hours, with solvents such as N,N-dimethylformamide.
Without significantly sacrificing material fluidity, the flame retardant and smoke-suppressing properties and thermal stability of silicone oil are improved, while maintaining good fluidity and viscosity, facilitating the modification and processing of polymer materials, and providing excellent flame retardant and smoke-suppressing effects.
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Figure CN122167471A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of modified silicone oil technology, and in particular to low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil and its preparation method. Background Technology
[0002] Epoxy silicone oil possesses excellent high-temperature resistance, weather resistance, and compatibility, and is commonly used as a toughening modifier for epoxy resins, a modifying component for electronic encapsulation adhesives, and an interface modifier for composite materials. It is widely applied in the modification of polymer materials in electronics, high-end textiles, and resin-based composites. However, pure epoxy silicone oil has poor flame retardant properties and produces large amounts of smoke and toxic gases when burning, limiting its application in scenarios with high fire safety requirements, such as rail transportation and new energy electronics. Currently, methods for flame-retardant modification of epoxy silicone oil mainly include adding halogen-based, phosphorus-based, and inorganic flame retardants, but additive methods... Flame retardants suffer from problems such as large addition amounts, poor compatibility with the matrix, and impact on the mechanical properties of materials. However, chemical modification methods, by introducing flame retardant groups such as phosphorus and nitrogen into the epoxy silicone oil molecular chain, can improve the flame retardant and smoke suppression performance while also enhancing the heat resistance and mechanical toughness of the material, achieving a synergistic improvement in both flame retardant performance and material performance. This has become a current research hotspot. However, this method still has problems such as insufficient flowability and increased viscosity due to the addition of flame retardants, complex and costly synthesis processes for highly efficient flame retardant products, and the tendency of introducing flame retardant groups to reduce the reactivity and crosslinking density of epoxy resins. Further optimization and improvement are needed. Summary of the Invention
[0003] Based on the technical problems existing in the background technology, the present invention proposes a low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil and its preparation method.
[0004] This invention proposes a low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil. The flame-retardant and smoke-suppressing silicone oil is obtained by a ring-opening addition reaction between a double-ended epoxy silicone oil and methylurea. Its molecular structure is as follows: ; The value of n ranges from 1 to 3.
[0005] Preferably, the epoxy value of the terminal epoxy silicone oil is 0.45-0.60 mol / 100g, and the number average molecular weight is 360-400 g / mol.
[0006] Preferably, the low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil has a viscosity of 2500-2700 mPa·s at 25°C, a maximum decomposition temperature of 360-403°C, and a carbon residue of 3.20-4.66% at 800°C.
[0007] The present invention proposes a method for preparing low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil, wherein the flame-retardant and smoke-suppressing silicone oil is as described in any one of claims 1-3, characterized in that the method comprises the following steps: mixing and reacting terminal epoxy silicone oil, methyl urea and catalyst in a solvent to obtain low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil.
[0008] Preferably, the molar ratio of terminal epoxy silicone oil to methylurea is 1:1.5-2.5.
[0009] Preferably, the reaction conditions are a temperature of 130-150℃ and a time of 4-6 hours.
[0010] Preferably, the catalyst is one or more of 2,4,6-tris(dimethylaminomethyl)phenol, triethylamine, benzyldimethylamine, and triethylenediamine.
[0011] Preferably, the amount of catalyst added is 0.3-0.4% of the total mass of the terminal epoxy silicone oil and methylurea.
[0012] Preferably, the solvent is one or more of N,N-dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone.
[0013] The present invention relates to the application of the aforementioned low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil in polymer materials.
[0014] Beneficial technical effects of the present invention: (1) This invention uses methylurea to chemically modify end-epoxy silicone oil, introducing nitrogen-containing groups into the polysiloxane molecule in a reactive manner, thereby improving the flame retardant and smoke-suppressing properties and thermal stability of the silicone oil without significantly sacrificing the material's flowability. The resulting low-viscosity nitrogen-modified flame retardant and smoke-suppressing silicone oil maintains good flowability at room temperature, with a viscosity of 2500~2700 mPa·s, facilitating its use in polymer modification, composite system blending, and subsequent processing applications.
[0015] (2) This invention introduces methylurea groups at both ends of the epoxy silicone oil, enabling the material to exert a flame-retardant and smoke-suppressing effect due to its nitrogen-containing structure during thermal decomposition. On the one hand, the gaseous products released during the thermal decomposition of the nitrogen-containing groups help dilute the combustible components and oxygen concentration in the combustion zone and remove some heat, thereby inhibiting flame propagation. On the other hand, the modified polysiloxane system has a higher tendency to leave char residue during combustion, which is conducive to forming a certain barrier layer, thereby slowing down the further transfer of heat and combustible volatiles. Therefore, the low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil prepared by this invention has good fluidity, high thermal stability, and superior flame-retardant and smoke-suppressing performance, and has good application prospects. Attached Figure Description
[0016] Figure 1The thermogravimetric curves of the low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil and the terminal epoxy silicone oil proposed in this invention are shown.
[0017] Figure 2 A schematic diagram of the combustion of epoxy silicone oil.
[0018] Figure 3 This is a schematic diagram of the combustion of the low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil prepared in Example 1.
[0019] Figure 4 This is a schematic diagram of the combustion of the low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil prepared in Example 2.
[0020] Figure 5 This is a schematic diagram of the combustion of the low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil prepared in Example 3.
[0021] Figure 6 This is a schematic diagram of the combustion of the low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil prepared in Example 4.
[0022] Figure 7 This is a schematic diagram of the combustion of the low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil prepared in Example 5. Detailed Implementation
[0023] The present invention will be further explained below with reference to specific embodiments.
[0024] Example 1 Take 30g of terminal epoxy silicone oil, 9.02g of methylurea and 0.133g of 2,4,6-tris(dimethylaminomethyl)phenol, add them to 78ml of N,N-dimethylformamide, stir to dissolve, heat the mixed solution to 140℃, and keep it at this temperature for 5h under nitrogen protection to obtain the product.
[0025] The product was subjected to vacuum distillation for 3 hours in a vacuum oven at 90℃ and -85kPa to remove N,N-dimethylformamide. The product was then washed three times with 500ml of deionized water at 50℃ to remove methylurea and 2,4,6-tris(dimethylaminomethyl)phenol. The washed product was then dried in a vacuum drying oven at -85kPa and 85℃ for 5 hours to obtain a low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil with a viscosity of 2550 mPa·s at room temperature.
[0026] See Figure 1 The low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil prepared in Example 1 has a maximum decomposition temperature of 360°C and a carbon residue of 4.13% at 800°C.
[0027] See Figure 3The low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil prepared in Example 1 produces virtually no black smoke after ignition, and the flame height is 8.5 cm.
[0028] Example 2 Take 30g of terminal epoxy silicone oil, 10.83g of methylurea and 0.139g of 2,4,6-tris(dimethylaminomethyl)phenol, add them to 81.7ml of N,N-dimethylformamide, stir to dissolve, heat the mixed solution to 140℃, and keep it at this temperature for 5h under nitrogen protection to obtain the product.
[0029] The product was subjected to vacuum distillation for 3 hours in a vacuum oven at 90℃ and -85kPa to remove N,N-dimethylformamide. The product was then washed three times with 500 ml of deionized water at 50℃ to remove methylurea and 2,4,6-tris(dimethylaminomethyl)phenol. The washed product was then dried in a vacuum drying oven at -85kPa and 85℃ for 5 hours to obtain a low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil with a viscosity of 2600 mPa·s at room temperature.
[0030] See Figure 1 The low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil prepared in Example 2 has a maximum decomposition temperature of 403℃ and a carbon residue of 3.20% at 800℃.
[0031] See Figure 4 The low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil prepared in Example 2 produces virtually no black smoke after ignition, and the flame height is 4.2 cm.
[0032] Example 3 Take 30g of terminal epoxy silicone oil, 12.03g of methylurea and 0.143g of 2,4,6-tris(dimethylaminomethyl)phenol, add them to 84.1ml of N,N-dimethylformamide, stir to dissolve, heat the mixed solution to 140℃, and keep it at this temperature for 5h under nitrogen protection to obtain the product.
[0033] The product was subjected to vacuum distillation for 3 hours in a vacuum oven at 90℃ and -85kPa to remove N,N-dimethylformamide. The product was then washed three times with 500 ml of deionized water at 50℃ to remove methylurea and 2,4,6-tris(dimethylaminomethyl)phenol. The washed product was then dried in a vacuum drying oven at -85kPa and 85℃ for 5 hours to obtain a low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil with a viscosity of 2510 mPa·s at room temperature.
[0034] See Figure 1The low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil prepared in Example 3 has a maximum decomposition temperature of 368°C and a carbon residue of 4.66% at 800°C.
[0035] See Figure 5 The low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil prepared in Example 3 produces virtually no black smoke after ignition, and the flame height is 7.1 cm.
[0036] Example 4 Take 30g of terminal epoxy silicone oil, 13.23g of methylurea and 0.147g of 2,4,6-tris(dimethylaminomethyl)phenol, add them to 86.46ml of N,N-dimethylformamide, stir to dissolve, heat the mixed solution to 140℃, and keep it at this temperature for 5h under nitrogen protection to obtain the product.
[0037] The product was subjected to vacuum distillation for 3 hours in a vacuum oven at 90℃ and -85kPa to remove N,N-dimethylformamide. The product was then washed three times with 500 ml of deionized water at 50℃ to remove methylurea and 2,4,6-tris(dimethylaminomethyl)phenol. The washed product was then dried in a vacuum drying oven at -85kPa and 85℃ for 5 hours to obtain a low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil with a viscosity of 2667 mPa·s at room temperature.
[0038] See Figure 1 The low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil prepared in Example 4 has a maximum decomposition temperature of 391°C and a carbon residue of 3.52% at 800°C.
[0039] See Figure 6 The low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil prepared in Example 4 produces virtually no black smoke after ignition, and the flame height is 7.5 cm.
[0040] Example 5 Take 30g of terminal epoxy silicone oil, 15.03g of methylurea and 0.153g of 2,4,6-tris(dimethylaminomethyl)phenol, add them to 90.06ml of N,N-dimethylformamide, stir to dissolve, heat the mixed solution to 140℃, and keep it at this temperature for 5h under nitrogen protection to obtain the product.
[0041] The product was subjected to vacuum distillation for 3 hours in a vacuum oven at 90℃ and -85kPa to remove N,N-dimethylformamide. The product was then washed three times with 500 ml of deionized water at 50℃ to remove methylurea and 2,4,6-tris(dimethylaminomethyl)phenol. The washed product was then dried in a vacuum drying oven at -85kPa and 85℃ for 5 hours to obtain a low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil with a viscosity of 2630 mPa·s at room temperature.
[0042] See Figure 1 The low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil prepared in Example 5 has a maximum decomposition temperature of 394°C and a carbon residue of 3.67% at 800°C.
[0043] See Figure 7 The low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil prepared in Example 5 produces virtually no black smoke after ignition, and the flame height is 6.0 cm.
[0044] In summary, this invention utilizes methylurea to chemically modify end-epoxy silicone oil, introducing nitrogen-containing groups into the polysiloxane molecule in a reactive manner. This improves the flame-retardant and smoke-suppressing properties and thermal stability of the silicone oil without significantly sacrificing material flowability. The resulting low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil maintains good flowability at room temperature, with a viscosity of 2540~2630 mPa·s, facilitating its use in polymer modification, composite system blending, and subsequent processing applications.
[0045] Meanwhile, this invention introduces methylurea groups at both ends of the epoxy silicone oil, enabling the material to exert a nitrogen-containing structure for flame retardancy and smoke suppression during thermal decomposition. On one hand, the gaseous products released during the thermal decomposition of the nitrogen-containing groups help dilute the combustible components and oxygen concentration in the combustion zone and remove some heat, thereby inhibiting flame propagation. On the other hand, the modified polysiloxane system has a higher tendency for char residue during combustion, which is beneficial for forming a certain barrier layer, thereby slowing down the further transfer of heat and combustible volatiles. Therefore, the low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil prepared by this invention has good fluidity, high thermal stability, and superior flame-retardant and smoke-suppressing performance, and has good application prospects.
[0046] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application. The scope of this application is defined by the appended claims and their equivalents, all of which should be included within the protection scope of this application.
Claims
1. A low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil, characterized in that, Flame-retardant and smoke-suppressing silicone oil is obtained by a ring-opening addition reaction between double-ended epoxy silicone oil and methylurea. The molecular structure is as follows: ； The value of n ranges from 1 to 3.
2. The low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil according to claim 1, characterized in that, The epoxy value of the terminal epoxy silicone oil is 0.45-0.60 mol / 100g, and the number average molecular weight is 360-400 g / mol.
3. The low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil according to claim 1 or 2, characterized in that, The low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil has a viscosity of 2500-2700 mPa·s at 25℃, a maximum decomposition temperature of 360-403℃, and a carbon residue of 3.20-4.66% at 800℃.
4. A method for preparing a low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil, wherein the flame-retardant and smoke-suppressing silicone oil is as described in any one of claims 1-3, characterized in that, The method steps are as follows: terminal epoxy silicone oil, methyl urea and catalyst are mixed and reacted in a solvent to obtain low viscosity nitrogen-modified flame retardant and smoke-suppressing silicone oil.
5. The method for preparing low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil according to claim 4, characterized in that, The molar ratio of terminal epoxy silicone oil to methylurea is 1:1.5-2.
5.
6. The method for preparing low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil according to claim 4, characterized in that, The reaction conditions are a temperature of 130-150℃ and a time of 4-6 hours.
7. The method for preparing low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil according to claim 4, characterized in that, The catalyst is one or more of 2,4,6-tris(dimethylaminomethyl)phenol, triethylamine, benzyldimethylamine and triethylenediamine.
8. The method for preparing low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil according to claim 4, characterized in that, The amount of catalyst added is 0.3-0.4% of the total mass of terminal epoxy silicone oil and methylurea.
9. The method for preparing low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil according to claim 2, characterized in that, The solvent is one or more of N,N-dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone.
10. The application of the low-viscosity nitrogen-modified flame-retardant and smoke-suppressing silicone oil as described in any one of claims 1-3 in polymeric materials.