A silicone resin flame retardant and a method for preparing the same

Abstract

The application provides a silicone resin flame retardant and a preparation method thereof, and belongs to the field of silicone flame retardants. Thiourea, tris(2-chloroethyl) phosphate and potassium hydroxide solution are reacted to obtain a thiolated phosphate ester; molybdenum disulfide is subjected to ultrasonic treatment to obtain flaky molybdenum disulfide; the flaky molybdenum disulfide and the thiolated phosphate ester are reacted to obtain modified molybdenum disulfide; and the modified molybdenum disulfide, modified silicone and lithium hydroxide are reacted to obtain the silicone resin flame retardant. The silicone resin flame retardant prepared by the application contains phosphorus, sulfur, nitrogen and silicon and the like, and the multiple elements are synergistic, so that the flame retardant efficiency is effectively improved; the silicone resin flame retardant has good compatibility and interface combination with the epoxy resin. The silicone flame retardant as a foreign phase can be avoided to cause stress concentration, and the mechanical properties of the epoxy resin are improved.

Description

Technical Field

[0001] This invention relates to the field of organosilicon flame retardants, and more specifically to an organosilicon resin flame retardant and its preparation method. Background Technology

[0002] Epoxy resins are widely used in electronic packaging, composite materials, coatings, and adhesives due to their excellent mechanical properties, adhesion, chemical resistance, and electrical insulation. However, epoxy resins are highly flammable and pose a significant fire hazard, making flame-retardant modification a critical requirement for safe material applications.

[0003] Traditional physically blended flame retardants, such as halogenated compounds, inorganic hydroxides, or phosphorus-based flame retardants, have inherent compatibility defects with epoxy resin matrices. From a molecular structure and chemical property perspective, these flame retardants differ significantly from epoxy resins in polarity and intermolecular forces, making it difficult for them to form a stable homogeneous system. Phase separation easily occurs during the blending process. This phase separation phenomenon is more pronounced when the material is used for a long time or exposed to high temperatures, causing the flame retardant to gradually migrate and precipitate from the epoxy resin matrix, forming a "frosting" phenomenon on the surface of the product.

[0004] Currently, most flame retardants rely on a single flame-retardant mechanism. For example, halogenated flame retardants mainly inhibit combustion reactions through gas-phase flame retardancy, while phosphorus-based flame retardants primarily rely on char formation to create a protective layer on the material surface. However, the flame-retardant efficiency of a single mechanism is limited and cannot meet increasingly stringent flame-retardant standards, such as UL94 V-0. To meet these high standards, it is necessary to continue increasing the amount of flame retardant added, which creates a vicious cycle: while high addition amounts improve flame-retardant performance to some extent, they further exacerbate the loss of mechanical properties and increase processing difficulty.

[0005] Invention patent CN112679803B discloses a graphene nanosheet-loaded tin flame retardant, a flame-retardant epoxy resin, and a method for preparing the two. The graphene nanosheet-loaded tin flame retardant is mixed with hexa(p-hydroxymethylphenoxy)-cyclotriphosphazene and added to the epoxy resin as a composite flame retardant, which can significantly improve the flame retardant effect of the epoxy resin. However, graphene itself is prone to agglomeration, which may have an adverse effect on the mechanical properties of the epoxy resin.

[0006] Therefore, providing a flame retardant with good flame retardant properties while avoiding adverse effects on the mechanical properties of epoxy resin is an important problem that urgently needs to be solved in this field. Summary of the Invention

[0007] To address the shortcomings of existing technologies, an organosilicon resin flame retardant and its preparation method are provided. Specifically, the technical solution of this invention includes the following:

[0008] A method for preparing an organosilicon resin flame retardant, the method comprising the following steps:

[0009] Thiourea, tri(2-chloroethyl) phosphate, and potassium hydroxide solution were reacted to yield thiolated phosphate ester;

[0010] Molybdenum disulfide was ultrasonically processed to obtain flake-shaped molybdenum disulfide.

[0011] Modified molybdenum disulfide is obtained by reacting flake-shaped molybdenum disulfide with thiolated phosphate ester;

[0012] The organosilicon resin flame retardant was prepared by reacting modified molybdenum disulfide, modified organosilicon, and lithium hydroxide.

[0013] Furthermore, the weight ratio of the thiourea, tri(2-chloroethyl) phosphate, and potassium hydroxide solution is 8.7~9.1:10:20~25.

[0014] Furthermore, the potassium hydroxide solution is a 15% potassium hydroxide solution by mass.

[0015] Furthermore, the reaction conditions for the thiourea, tri(2-chloroethyl) phosphate and potassium hydroxide solution include a reaction temperature of 60-80°C and a reaction time of 6-8 hours.

[0016] Furthermore, the conditions for the ultrasonic treatment include a processing power of 500-600W and a processing time of 2-3 hours.

[0017] Furthermore, the weight ratio of the flake molybdenum disulfide to the thiol phosphate is 1:10~11.

[0018] Furthermore, the reaction conditions for the flake molybdenum disulfide and the thiolized phosphate ester include a reaction temperature of 23-25°C and a reaction time of 24-28 h.

[0019] Furthermore, the preparation method of the modified organosilicon includes the following steps:

[0020] 1,3,5,7-Tetramethylcyclotetrasiloxane, allyl glycidyl ether and acryloyl chloride were mixed to obtain a mixture, and then chloroplatinic acid and tri-n-butylamine were added and reacted to obtain an intermediate.

[0021] The modified organosilicon was prepared by reacting an intermediate, a polyetheramine, a surfactant, and sodium hydroxide.

[0022] Further, the weight ratio of 1,3,5,7-tetramethylcyclotetrasiloxane, allyl glycidyl ether, acryloyl chloride, chloroplatinic acid and tri-n-butylamine is 10:9.7~10.3:7.2~7.6:0.003~0.004:0.001~0.0015.

[0023] Furthermore, the reaction conditions for the mixture, chloroplatinic acid, and tri-n-butylamine include a reaction temperature of 65-85°C and a reaction time of 3-5 hours.

[0024] Furthermore, the polyetheramine is polyetheramine D230.

[0025] Furthermore, the surfactant is sodium dodecylbenzenesulfonate.

[0026] Further, the weight ratio of the intermediate, polyetheramine, surfactant and sodium hydroxide is 1:1.3~1.5:0.06~0.08:0.08~0.1.

[0027] Furthermore, the reaction conditions for the intermediate, polyetheramine, surfactant and sodium hydroxide include a reaction temperature of 0~5℃ and a reaction time of 12~16h.

[0028] Furthermore, the weight ratio of the modified molybdenum disulfide, modified organosilicon, and lithium hydroxide is 2~3:3~5:0.01~0.02.

[0029] Furthermore, the reaction conditions for the modified molybdenum disulfide, modified organosilicon, and lithium hydroxide include a reaction temperature of 40-50°C and a reaction time of 26-36 h.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] (1) In this invention, the Si-H bond in 1,3,5,7-tetramethylcyclotetrasiloxane undergoes hydrosilylation reaction with the olefins in allyl glycidyl ether and acryloyl chloride to obtain an intermediate containing epoxy and acryl chloride groups; the amino group of polyetheramine D230 reacts with the acryl chloride of the intermediate to obtain modified organosilicon; after the reaction of thiourea and tri(2-chloroethyl) phosphate, it is hydrolyzed in an alkaline environment to obtain mercapto-containing thiolated phosphate; molybdenum disulfide is ultrasonically exfoliated to obtain flake molybdenum disulfide; the mercapto group of the thiolated phosphate coordinates with the sulfur defect site on the surface of the flake molybdenum disulfide to modify the flake molybdenum disulfide to obtain modified molybdenum disulfide; the mercapto group of the modified molybdenum disulfide reacts with the epoxy group of the modified organosilicon to prepare an organosilicon resin flame retardant.

[0032] (2) The organosilicon resin flame retardant prepared by the present invention contains multiple elements such as phosphorus, sulfur, nitrogen and silicon, and has a good flame retardant effect during combustion. Among them, phosphorus, nitrogen and silicon elements can synergistically promote the formation of expanded char layer during combustion, and isolate heat and oxygen through condensed phase flame retardancy. Phosphorus, nitrogen and sulfur elements interrupt the combustion chain reaction through gas phase flame retardancy. In addition, modified molybdenum disulfide is uniformly dispersed in epoxy resin during processing, and can be intercalated into the char layer during combustion, further enhancing the physical barrier properties of the char layer. Through the synergistic effect of the above multiple elements, the flame retardant efficiency of flame retardant epoxy resin is effectively improved.

[0033] (3) The organosilicon flame retardant prepared by the present invention contains abundant active groups, which can participate in the curing reaction of epoxy resin. It can be embedded into the cross-linking network of epoxy resin through chemical bonding and become part of its network structure, effectively improving the compatibility between organosilicon flame retardant and epoxy resin groups and enhancing the interfacial bonding strength. Good compatibility and interfacial bonding can avoid the stress concentration problem caused by organosilicon flame retardant as a foreign phase, thereby reliably maintaining the mechanical properties of epoxy resin. Detailed Implementation

[0034] The technical solution of the present invention will be clearly and completely described below through embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Unless otherwise stated, all raw materials and reagents used in this invention are commercially available or can be prepared by known methods.

[0036] Preparation Example 1:

[0037] The preparation method of modified organosilicon includes the following steps:

[0038] 10 parts by weight of 1,3,5,7-tetramethylcyclotetrasiloxane, 9.7 parts by weight of allyl glycidyl ether and 7.2 parts by weight of acryloyl chloride were dispersed in 200 parts by weight of toluene to obtain a mixture. Under nitrogen protection, 0.003 parts by weight of chloroplatinic acid and 0.001 parts by weight of tri-n-butylamine were added, the temperature was raised to 65°C and the mixture was stirred for 3 hours. After the reaction was completed, the intermediate was obtained by vacuum distillation.

[0039] 10 parts by weight of intermediate and 13 parts by weight of polyetheramine D230 were dispersed in 500 parts by weight of dichloromethane, and 0.6 parts by weight of sodium dodecylbenzenesulfonate and 0.8 parts by weight of sodium hydroxide were added. The mixture was cooled to 0°C and stirred for 12 h. After the reaction was completed, the mixture was distilled under reduced pressure, washed with deionized water and ethanol, and dried under vacuum at 60°C for 8 h to obtain modified organosilicon.

[0040] Preparation Example 2:

[0041] The preparation method of modified organosilicon includes the following steps:

[0042] 10 parts by weight of 1,3,5,7-tetramethylcyclotetrasiloxane, 9.8 parts by weight of allyl glycidyl ether and 7.3 parts by weight of acryloyl chloride were dispersed in 200 parts by weight of toluene to obtain a mixture. Under nitrogen protection, 0.0032 parts by weight of chloroplatinic acid and 0.0011 parts by weight of tri-n-butylamine were added, the temperature was raised to 70°C and the mixture was stirred for 3.5 h. After the reaction was completed, the intermediate was obtained by vacuum distillation.

[0043] 10 parts by weight of intermediate and 13.5 parts by weight of polyetheramine D230 were dispersed in 500 parts by weight of dichloromethane. 0.65 parts by weight of sodium dodecylbenzenesulfonate and 0.85 parts by weight of sodium hydroxide were added. The mixture was cooled to 1°C and stirred for 13 hours. After the reaction was completed, the mixture was distilled under reduced pressure, washed with deionized water and ethanol, and dried under vacuum at 65°C for 9 hours to obtain modified organosilicon.

[0044] Preparation Example 3:

[0045] The preparation method of modified organosilicon includes the following steps:

[0046] 10 parts by weight of 1,3,5,7-tetramethylcyclotetrasiloxane, 9.9 parts by weight of allyl glycidyl ether and 7.4 parts by weight of acryloyl chloride were dispersed in 200 parts by weight of toluene to obtain a mixture. Under nitrogen protection, 0.0034 parts by weight of chloroplatinic acid and 0.0012 parts by weight of tri-n-butylamine were added, and the mixture was heated to 75°C and stirred for 4 hours. After the reaction was completed, the intermediate was obtained by vacuum distillation.

[0047] 10 parts by weight of intermediate and 14 parts by weight of polyetheramine D230 were dispersed in 500 parts by weight of dichloromethane, and 0.7 parts by weight of sodium dodecylbenzenesulfonate and 0.9 parts by weight of sodium hydroxide were added. The mixture was cooled to 2°C and stirred for 14 h. After the reaction was completed, the mixture was distilled under reduced pressure, washed with deionized water and ethanol, and dried under vacuum at 70°C for 10 h to obtain modified organosilicon.

[0048] Preparation Example 4:

[0049] The preparation method of modified organosilicon includes the following steps:

[0050] 10 parts by weight of 1,3,5,7-tetramethylcyclotetrasiloxane, 10.1 parts by weight of allyl glycidyl ether and 7.5 parts by weight of acryloyl chloride were dispersed in 200 parts by weight of toluene to obtain a mixture. Under nitrogen protection, 0.0037 parts by weight of chloroplatinic acid and 0.0014 parts by weight of tri-n-butylamine were added, and the mixture was heated to 80°C and stirred for 4.5 h. After the reaction was completed, the intermediate was obtained by vacuum distillation.

[0051] 10 parts by weight of intermediate and 14.5 parts by weight of polyetheramine D230 were dispersed in 500 parts by weight of dichloromethane. 0.75 parts by weight of sodium dodecylbenzenesulfonate and 0.95 parts by weight of sodium hydroxide were added. The mixture was cooled to 4°C and stirred for 15 h. After the reaction was completed, the mixture was distilled under reduced pressure, washed with deionized water and ethanol, and dried under vacuum at 75°C for 11 h to obtain modified organosilicon.

[0052] Preparation Example 5:

[0053] The preparation method of modified organosilicon includes the following steps:

[0054] 10 parts by weight of 1,3,5,7-tetramethylcyclotetrasiloxane, 10.3 parts by weight of allyl glycidyl ether and 7.6 parts by weight of acryloyl chloride were dispersed in 200 parts by weight of toluene to obtain a mixture. Under nitrogen protection, 0.004 parts by weight of chloroplatinic acid and 0.0015 parts by weight of tri-n-butylamine were added, and the mixture was heated to 85°C and stirred for 5 hours. After the reaction was completed, the intermediate was obtained by vacuum distillation.

[0055] 10 parts by weight of intermediate and 15 parts by weight of polyetheramine D230 were dispersed in 500 parts by weight of dichloromethane, 0.8 parts by weight of sodium dodecylbenzenesulfonate and 1 part by weight of sodium hydroxide were added, the mixture was cooled to 5°C and stirred for 16 h, after which the reaction was carried out by vacuum distillation, washed with deionized water and ethanol, and dried under vacuum at 80°C for 12 h to obtain modified organosilicon.

[0056] Preparation Example 6:

[0057] The preparation method of modified organosilicon includes the following steps:

[0058] 10 parts by weight of 1,3,5,7-tetramethylcyclotetrasiloxane and 20 parts by weight of allyl glycidyl ether were dispersed in 200 parts by weight of toluene to obtain a mixture. Under nitrogen protection, 0.004 parts by weight of chloroplatinic acid and 0.0015 parts by weight of tri-n-butylamine were added, and the mixture was heated to 85°C and stirred for 5 hours. After the reaction was completed, the modified organosilicon was obtained by vacuum distillation.

[0059] Preparation Example 7:

[0060] The preparation method of modified organosilicon includes the following steps:

[0061] 10 parts by weight of 1,3,5,7-tetramethylcyclotetrasiloxane and 20 parts by weight of acryloyl chloride were dispersed in 200 parts by weight of toluene to obtain a mixture. Under nitrogen protection, 0.004 parts by weight of chloroplatinic acid and 0.0015 parts by weight of tri-n-butylamine were added, the temperature was raised to 85°C and the mixture was stirred for 5 hours. After the reaction was completed, the intermediate was obtained by vacuum distillation.

[0062] 10 parts by weight of intermediate and 15 parts by weight of polyetheramine D230 were dispersed in 500 parts by weight of dichloromethane, 0.8 parts by weight of sodium dodecylbenzenesulfonate and 1 part by weight of sodium hydroxide were added, the mixture was cooled to 5°C and stirred for 16 h, after which the reaction was carried out by vacuum distillation, washed with deionized water and ethanol, and dried under vacuum at 80°C for 12 h to obtain modified organosilicon.

[0063] Example 1:

[0064] A method for preparing an organosilicon resin flame retardant includes the following steps:

[0065] 8.7 parts by weight of thiourea were dispersed in 200 parts by weight of 95% ethanol, heated to 40°C and stirred for 5 min. 10 parts by weight of tris(2-chloroethyl) phosphate were added, heated to 60°C and stirred for 1 h. 20 parts by weight of 15% potassium hydroxide solution were added, and the reaction was continued to be stirred for 6 h. After the reaction was completed, the pH was adjusted to 9, the organic layer was collected, dried with anhydrous magnesium sulfate, filtered and distilled under normal pressure to obtain thiol phosphate.

[0066] 1 part by weight of few-layer molybdenum disulfide powder is dispersed in 150 parts by weight of mixed solvent (V N-甲基吡咯烷酮 V 30%H2O2 =15:1), ultrasonically treated with 500W power for 2h, centrifuged at 6000r / min for 15min after treatment, washed 3 times with deionized water, and vacuum dried at 50℃ for 8h to obtain flake molybdenum disulfide;

[0067] One part by weight of flake molybdenum disulfide was dispersed in 300 parts by weight of N-methylpyrrolidone and ultrasonicated for 40 min to obtain a dispersion. 11 parts by weight of thiol phosphate were added and the mixture was stirred at 23 °C for 24 h. After the reaction was completed, the mixture was centrifuged at 5000 r / min for 15 min, washed three times with ethanol, and dried under vacuum at 50 °C for 8 h to obtain modified molybdenum disulfide.

[0068] Two parts by weight of modified molybdenum disulfide and three parts by weight of the modified organosilicon prepared in Example 1 were dispersed in 50 parts by weight of a mixed solution (V DMF V 去离子水 In a mixture of 9:1, 0.01 parts by weight of lithium hydroxide was added, and the mixture was stirred at 40°C for 24 hours. After the reaction was completed, the pH was adjusted to 7, and the silicone resin flame retardant was obtained by centrifugation, washing and vacuum drying.

[0069] The preparation method of flame-retardant epoxy resin includes the following steps:

[0070] 80 parts by weight of epoxy resin E51 and 5 parts by weight of the above-prepared silicone resin flame retardant were stirred and mixed at 120°C for 30 min, and then 20 parts by weight of diaminodiphenylmethane were added and stirred for another 10 min to obtain a mixture. The mixture was placed in a 120°C environment for vacuum degassing, poured into a preheated mold, cured at 120°C for 2 h, then heated to 170°C for 4 h, and cooled to room temperature to obtain flame-retardant epoxy resin.

[0071] Example 2:

[0072] A method for preparing an organosilicon resin flame retardant includes the following steps:

[0073] 8.8 parts by weight of thiourea were dispersed in 200 parts by weight of 95% ethanol, heated to 40°C and stirred for 6 min. 10 parts by weight of tris(2-chloroethyl) phosphate were added, heated to 65°C and stirred for 1.2 h. 21 parts by weight of 15% potassium hydroxide solution were added, and the reaction was continued to be stirred for 6.5 h. After the reaction was completed, the pH was adjusted to 9.2. The organic layer was collected, dried with anhydrous magnesium sulfate, filtered, and distilled under normal pressure to obtain thiol phosphate.

[0074] 1 part by weight of few-layer molybdenum disulfide powder is dispersed in 150 parts by weight of mixed solvent (V N-甲基吡咯烷酮 V 30%H2O2 =15:1), ultrasonically treated with 520W power for 2.2h, centrifuged at 6000r / min for 15min after treatment, washed 3 times with deionized water, and vacuum dried at 52℃ for 9h to obtain flake molybdenum disulfide;

[0075] One part by weight of flake molybdenum disulfide was dispersed in 300 parts by weight of N-methylpyrrolidone and sonicated for 25 min to obtain a dispersion. 10.2 parts by weight of thiol phosphate was added and the mixture was stirred at 24 °C for 25 h. After the reaction was completed, the mixture was centrifuged at 5000 r / min for 15 min, washed three times with ethanol, and dried under vacuum at 52 °C for 9 h to obtain modified molybdenum disulfide.

[0076] 2.2 parts by weight of modified molybdenum disulfide and 3.5 parts by weight of the modified organosilicon prepared in Example 2 were dispersed in 50 parts by weight of a mixed solution (V DMF V 去离子水 In a mixture of 9:1, 0.012 parts by weight of lithium hydroxide was added, and the mixture was stirred at 42°C for 28 hours. After the reaction was completed, the pH was adjusted to 7.2, and the mixture was then centrifuged, washed, and vacuum dried to obtain the organosilicon resin flame retardant.

[0077] The preparation method of flame-retardant epoxy resin includes the following steps:

[0078] 80 parts by weight of epoxy resin E51 and 5 parts by weight of the above-prepared silicone resin flame retardant were stirred and mixed at 120°C for 30 min, and then 20 parts by weight of diaminodiphenylmethane were added and stirred for another 10 min to obtain a mixture. The mixture was placed in a 120°C environment for vacuum degassing, poured into a preheated mold, cured at 120°C for 2 h, then heated to 170°C for 4 h, and cooled to room temperature to obtain flame-retardant epoxy resin.

[0079] Example 3:

[0080] A method for preparing an organosilicon resin flame retardant includes the following steps:

[0081] 8.9 parts by weight of thiourea were dispersed in 200 parts by weight of 95% ethanol, heated to 40°C and stirred for 7 min. 10 parts by weight of tris(2-chloroethyl) phosphate were added, heated to 70°C and stirred for 1.5 h. 22 parts by weight of 15% potassium hydroxide solution were added, and the reaction was continued to be stirred for 7 h. After the reaction was completed, the pH was adjusted to 9.5, the organic layer was collected, dried with anhydrous magnesium sulfate, filtered and distilled under normal pressure to obtain thiol phosphate.

[0082] 1 part by weight of few-layer molybdenum disulfide powder is dispersed in 150 parts by weight of mixed solvent (V N-甲基吡咯烷酮 V 30%H2O2 =15:1), ultrasonically treated with 550W power for 2.5h, centrifuged at 6000r / min for 15min after treatment, washed 3 times with deionized water, and vacuum dried at 55℃ for 10h to obtain flake molybdenum disulfide;

[0083] One part by weight of flake molybdenum disulfide was dispersed in 300 parts by weight of N-methylpyrrolidone and sonicated for 30 min to obtain a dispersion. 10.5 parts by weight of thiol phosphate was added and the mixture was stirred at 23 °C for 26 h. After the reaction was completed, the mixture was centrifuged at 5000 r / min for 15 min, washed three times with ethanol, and dried under vacuum at 55 °C for 10 h to obtain modified molybdenum disulfide.

[0084] 2.5 parts by weight of modified molybdenum disulfide and 4 parts by weight of the modified organosilicon prepared in Example 3 were dispersed in 50 parts by weight of a mixed solution (V DMF V 去离子水 In a mixture of 9:1, 0.015 parts by weight of lithium hydroxide was added, and the mixture was stirred at 45°C for 32 hours. After the reaction was completed, the pH was adjusted to 7.5, and the silicone resin flame retardant was obtained by centrifugation, washing and vacuum drying.

[0085] The preparation method of flame-retardant epoxy resin includes the following steps:

[0086] 80 parts by weight of epoxy resin E51 and 5 parts by weight of the above-prepared silicone resin flame retardant were stirred and mixed at 120°C for 30 min, and then 20 parts by weight of diaminodiphenylmethane were added and stirred for another 10 min to obtain a mixture. The mixture was placed in a 120°C environment for vacuum degassing, poured into a preheated mold, cured at 120°C for 2 h, then heated to 170°C for 4 h, and cooled to room temperature to obtain flame-retardant epoxy resin.

[0087] Example 4:

[0088] A method for preparing an organosilicon resin flame retardant includes the following steps:

[0089] 9.0 parts by weight of thiourea were dispersed in 200 parts by weight of 95% ethanol, heated to 40°C and stirred for 8 min. 10 parts by weight of tri(2-chloroethyl) phosphate were added, heated to 75°C and stirred for 1.7 h. 23 parts by weight of 15% potassium hydroxide solution were added, and the reaction was continued with stirring for 7.5 h. After the reaction was completed, the pH was adjusted to 9.8. The organic layer was collected, dried with anhydrous magnesium sulfate, filtered, and distilled under normal pressure to obtain thiolized phosphate.

[0090] 1 part by weight of few-layer molybdenum disulfide powder is dispersed in 150 parts by weight of mixed solvent (V N-甲基吡咯烷酮 V 30%H2O2 =15:1), ultrasonically treated with 570W power for 2.7h, centrifuged at 6000r / min for 15min after treatment, washed with deionized water 3 times, and vacuum dried at 57℃ for 11h to obtain flake molybdenum disulfide;

[0091] One part by weight of flake molybdenum disulfide was dispersed in 300 parts by weight of N-methylpyrrolidone and sonicated for 35 min to obtain a dispersion. 10.8 parts by weight of thiolated phosphate was added and the mixture was stirred at 25 °C for 27 h. After the reaction was completed, the mixture was centrifuged at 5000 r / min for 15 min, washed three times with ethanol, and dried under vacuum at 57 °C for 11 h to obtain modified molybdenum disulfide.

[0092] 2.7 parts by weight of modified molybdenum disulfide and 4.5 parts by weight of the modified organosilicon prepared in Example 4 were dispersed in 50 parts by weight of a mixed solution (V DMF V 去离子水 In a mixture of 9:1, 0.018 parts by weight of lithium hydroxide was added, and the mixture was stirred at 47°C for 34 hours. After the reaction was completed, the pH was adjusted to 7.8, and the mixture was then centrifuged, washed, and vacuum dried to obtain the organosilicon resin flame retardant.

[0093] The preparation method of flame-retardant epoxy resin includes the following steps:

[0094] 80 parts by weight of epoxy resin E51 and 5 parts by weight of the above-prepared silicone resin flame retardant were stirred and mixed at 120°C for 30 min, and then 20 parts by weight of diaminodiphenylmethane were added and stirred for another 10 min to obtain a mixture. The mixture was placed in a 120°C environment for vacuum degassing, poured into a preheated mold, cured at 120°C for 2 h, then heated to 170°C for 4 h, and cooled to room temperature to obtain flame-retardant epoxy resin.

[0095] Example 5:

[0096] A method for preparing an organosilicon resin flame retardant includes the following steps:

[0097] 9.1 parts by weight of thiourea were dispersed in 200 parts by weight of 95% ethanol, heated to 40°C and stirred for 10 min. 10 parts by weight of tris(2-chloroethyl) phosphate were added, heated to 80°C and stirred for 2 h. 25 parts by weight of 15% potassium hydroxide solution were added, and the reaction was continued to be stirred for 8 h. After the reaction was completed, the pH was adjusted to 10, the organic layer was collected, dried with anhydrous magnesium sulfate, filtered and distilled under normal pressure to obtain thiol phosphate.

[0098] 1 part by weight of few-layer molybdenum disulfide powder is dispersed in 150 parts by weight of mixed solvent (V N-甲基吡咯烷酮 V 30%H2O2 =15:1), ultrasonically treated with 600W power for 3h, centrifuged at 6000r / min for 15min after treatment, washed 3 times with deionized water, and vacuum dried at 60℃ for 12h to obtain flake molybdenum disulfide;

[0099] One part by weight of flake molybdenum disulfide was dispersed in 300 parts by weight of N-methylpyrrolidone and sonicated for 40 min to obtain a dispersion. 11 parts by weight of thiol phosphate were added and the mixture was stirred at 25 °C for 28 h. After the reaction was completed, the mixture was centrifuged at 5000 r / min for 15 min, washed three times with ethanol, and dried under vacuum at 60 °C for 12 h to obtain modified molybdenum disulfide.

[0100] 3 parts by weight of modified molybdenum disulfide and 5 parts by weight of the modified organosilicon prepared in Example 5 were dispersed in 50 parts by weight of a mixed solution (V DMF V 去离子水 In a mixture of 9:1, 0.02 parts by weight of lithium hydroxide were added, and the mixture was stirred at 50°C for 36 hours. After the reaction was completed, the pH was adjusted to 8, and the product was obtained by centrifugation, washing, and vacuum drying.

[0101] The preparation method of flame-retardant epoxy resin includes the following steps:

[0102] 80 parts by weight of epoxy resin E51 and 5 parts by weight of the above-prepared silicone resin flame retardant were stirred and mixed at 120°C for 30 min, and then 20 parts by weight of diaminodiphenylmethane were added and stirred for another 10 min to obtain a mixture. The mixture was placed in a 120°C environment for vacuum degassing, poured into a preheated mold, cured at 120°C for 2 h, then heated to 170°C for 4 h, and cooled to room temperature to obtain flame-retardant epoxy resin.

[0103] Comparative Example 1:

[0104] A method for preparing an organosilicon resin flame retardant includes the following steps:

[0105] The modified organosilicon obtained in Preparation Example 5 was replaced with the modified organosilicon obtained in Preparation Example 6, and other operations were kept the same as in Preparation Example 5 to obtain an organosilicon resin flame retardant.

[0106] The preparation method of flame-retardant epoxy resin includes the following steps:

[0107] 80 parts by weight of epoxy resin E51 and 5 parts by weight of the above-prepared silicone resin flame retardant were stirred and mixed at 120°C for 30 min, and then 20 parts by weight of diaminodiphenylmethane were added and stirred for another 10 min to obtain a mixture. The mixture was placed in a 120°C environment for vacuum degassing, poured into a preheated mold, cured at 120°C for 2 h, then heated to 170°C for 4 h, and cooled to room temperature to obtain flame-retardant epoxy resin.

[0108] Comparative Example 2:

[0109] A method for preparing an organosilicon resin flame retardant includes the following steps:

[0110] The modified organosilicon prepared in Example 5 was replaced with the modified organosilicon prepared in Example 7, and other operations were kept the same as in Example 5 to obtain an organosilicon resin flame retardant.

[0111] The preparation method of flame-retardant epoxy resin includes the following steps:

[0112] 80 parts by weight of epoxy resin E51 and 5 parts by weight of the above-prepared silicone resin flame retardant were stirred and mixed at 120°C for 30 min, and then 20 parts by weight of diaminodiphenylmethane were added and stirred for another 10 min to obtain a mixture. The mixture was placed in a 120°C environment for vacuum degassing, poured into a preheated mold, cured at 120°C for 2 h, then heated to 170°C for 4 h, and cooled to room temperature to obtain flame-retardant epoxy resin.

[0113] Comparative Example 3:

[0114] The preparation method of flame-retardant epoxy resin includes the following steps:

[0115] 80 parts by weight of epoxy resin E51, 2.5 parts by weight of 1,3,5,7-tetramethylcyclotetrasiloxane and 2.5 parts by weight of molybdenum disulfide powder were stirred and mixed at 120°C for 30 min. Then, 20 parts by weight of diaminodiphenylmethane were added and the mixture was stirred for another 10 min to obtain a mixture. The mixture was placed in a vacuum environment at 120°C to remove bubbles, then poured into a preheated mold and cured at 120°C for 2 h. After curing at 170°C for 4 h, the temperature was raised to room temperature to obtain a flame-retardant epoxy resin.

[0116] Comparative Example 4:

[0117] The preparation method of flame-retardant epoxy resin includes the following steps:

[0118] 80 parts by weight of epoxy resin E51, 2 parts by weight of 1,3,5,7-tetramethylcyclotetrasiloxane, 2 parts by weight of molybdenum disulfide powder and 1 part by weight of tris(2-chloroethyl) phosphate were stirred and mixed at 120°C for 30 min. Then, 20 parts by weight of diaminodiphenylmethane were added and the mixture was stirred for another 10 min to obtain a mixture. After vacuum degassing in a 120°C environment, the mixture was poured into a preheated mold and cured at 120°C for 2 h. Then, the temperature was raised to 170°C and cured for 4 h. After cooling to room temperature, flame-retardant epoxy resin was obtained.

[0119] Comparative Example 5:

[0120] The preparation method of flame-retardant epoxy resin includes the following steps:

[0121] 80 parts by weight of epoxy resin E51 and 5 parts by weight of the modified organosilicon prepared in Preparation Example 5 were stirred and mixed at 120°C for 30 min, and then 20 parts by weight of diaminodiphenylmethane were added and stirred for another 10 min to obtain a mixture. After the mixture was placed in a vacuum degassing environment at 120°C, it was poured into a preheated mold and cured at 120°C for 2 h. Then, the temperature was raised to 170°C and cured for 4 h. After cooling to room temperature, flame-retardant epoxy resin was obtained.

[0122] Test Example 1: Combustion Performance Test

[0123] The limiting oxygen index of the flame-retardant epoxy resins prepared in Examples 1-5 and Comparative Examples 1-5 was measured using a limiting oxygen index meter according to ASTM D2863.

[0124] The flammability ratings of the flame-retardant epoxy resins prepared in Examples 1-5 and Comparative Examples 1-5 were tested according to the method in GB / T 2408-2008; the test results are shown in Table 1.

[0125] Table 1. Flame retardancy test

[0126]

[0127] The data in Table 1 show that the flame-retardant epoxy resins prepared by the organosilicon flame retardants in Examples 1-5 of this invention have good flame-retardant properties, while the flame-retardant epoxy resins prepared by Comparative Examples 1-5 all show varying degrees of performance degradation. The decreased flame retardant performance of Comparative Example 1 may be due to the use of only allyl glycidyl ether to modify 1,3,5,7-tetramethylcyclotetrasiloxane without the use of acryloyl chloride. This reduces the reaction sites of the silicone resin flame retardant, resulting in weaker bonding with the epoxy resin matrix and uneven dispersion within the matrix, ultimately leading to lower flame retardant performance. The decreased flame retardant performance of Comparative Example 2 may also be due to the absence of allyl glycidyl ether modification of 1,3,5,7-tetramethylcyclotetrasiloxane. The modified silicone cannot bind with the modified molybdenum disulfide, causing the silicone resin flame retardant to agglomerate, thus affecting the flame retardant performance of the epoxy resin. The decreased performance of Comparative Example 3 may be due to the direct application of 1,3,5,7-tetramethylcyclotetrasiloxane and molybdenum disulfide to the epoxy resin. Physical mixing of the matrix makes it difficult to produce a synergistic flame-retardant effect, thus affecting the flame-retardant performance of the epoxy resin. The decreased flame-retardant performance of Comparative Example 4 may be due to the direct physical mixing of 1,3,5,7-tetramethylcyclotetrasiloxane, molybdenum disulfide, and tri(2-chloroethyl) phosphate with the epoxy resin matrix. Although tri(2-chloroethyl) phosphate can provide gas-phase flame retardancy, the unmodified 1,3,5,7-tetramethylcyclotetrasiloxane and molybdenum disulfide have poor dispersibility and low char formation efficiency, ultimately affecting the flame-retardant performance of the epoxy resin. The decreased flame-retardant performance of Comparative Example 5 may be due to the use of only modified organosilicon as a flame retardant, lacking molybdenum disulfide and tri(2-chloroethyl) phosphate, which fails to form a synergistic flame-retardant effect, thus affecting the flame-retardant performance of the epoxy resin.

[0128] Test Example 2: Mechanical Property Testing

[0129] Tensile tests were conducted on the flame-retardant epoxy resins prepared in Examples 1-5 and Comparative Examples 1-5 using a UTM2203 tensile testing machine, with a loading speed of 2 mm / min. Bending tests were conducted on the flame-retardant epoxy resins prepared in Examples 1-5 and Comparative Examples 1-5 using a HUALONG WDW-5C electronic universal testing machine. The test results are shown in Table 2.

[0130] Table 2. Mechanical property testing

[0131]

[0132] The data in Table 2 show that the flame-retardant epoxy resins prepared by the organosilicon flame retardants in Examples 1-5 of this invention have good mechanical properties, while the mechanical properties of the flame-retardant epoxy resins prepared by Comparative Examples 1-5 all decreased to varying degrees. A comparison of Comparative Examples 1-2 with Example 5 reveals that dual modification of 1,3,5,7-tetramethylcyclotetrasiloxane using allyl glycidyl ether and acryloyl chloride enhances its bonding ability with modified molybdenum disulfide and epoxy resin. Furthermore, the introduction of polyetheramine enhances its compatibility and reactivity with epoxy resin groups. The decreased mechanical properties of Comparative Example 3 may be due to the agglomeration of unmodified molybdenum disulfide, and the lack of suitable reactive groups on the unmodified 1,3,5,7-tetramethylcyclotetrasiloxane leading to phase separation, thus affecting the mechanical properties of the flame-retardant epoxy resin. The decreased mechanical properties of Comparative Example 4 may be due to weak interfacial bonding resulting from only physical mixing of the unmodified components, affecting the mechanical properties of the flame-retardant epoxy resin. The decreased mechanical properties of Comparative Example 5 may be due to the use of only modified organosilicon, lacking the synergistic reinforcing effect of modified molybdenum disulfide.

[0133] The embodiments described above provide a detailed explanation of the technical solutions and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A method for preparing an organosilicon resin flame retardant, characterized in that, The preparation method includes the following steps: Thiourea, tri(2-chloroethyl) phosphate, and potassium hydroxide solution were reacted to yield thiolated phosphate ester; Molybdenum disulfide was ultrasonically processed to obtain flake-shaped molybdenum disulfide. Modified molybdenum disulfide is obtained by reacting flake-shaped molybdenum disulfide with thiolated phosphate ester; The organosilicon resin flame retardant was prepared by reacting modified molybdenum disulfide, modified organosilicon, and lithium hydroxide. The method for preparing the modified organosilicon includes the following steps: 1,3,5,7-Tetramethylcyclotetrasiloxane, allyl glycidyl ether and acryloyl chloride were mixed to obtain a mixture, and then chloroplatinic acid and tri-n-butylamine were added and reacted to obtain an intermediate. The modified organosilicon was prepared by reacting an intermediate, a polyetheramine, a surfactant, and sodium hydroxide.

2. The method for preparing an organosilicon resin flame retardant as described in claim 1, characterized in that, The weight ratio of thiourea, tri(2-chloroethyl) phosphate, and potassium hydroxide solution is 8.7~9.1:10:20~25.

3. The method for preparing an organosilicon resin flame retardant as described in claim 1, characterized in that, The weight ratio of the flake molybdenum disulfide to the thiolized phosphate is 1:10~11.

4. The method for preparing an organosilicon resin flame retardant as described in claim 1, characterized in that, The weight ratio of 1,3,5,7-tetramethylcyclotetrasiloxane, allyl glycidyl ether, acryloyl chloride, chloroplatinic acid and tri-n-butylamine is 10:9.7~10.3:7.2~7.6:0.003~0.004:0.001~0.0015.

5. The method for preparing an organosilicon resin flame retardant as described in claim 1, characterized in that, The polyetheramine is polyetheramine D230.

6. The method for preparing an organosilicon resin flame retardant as described in claim 1, characterized in that, The surfactant is sodium dodecylbenzenesulfonate.

7. The method for preparing an organosilicon resin flame retardant as described in claim 1, characterized in that, The weight ratio of the intermediate, polyetheramine, surfactant and sodium hydroxide is 1:1.3~1.5:0.06~0.08:0.08~0.

1.

8. The method for preparing an organosilicon resin flame retardant as described in claim 1, characterized in that, The weight ratio of the modified molybdenum disulfide, modified organosilicon, and lithium hydroxide is 2~3:3~5:0.01~0.

02.

9. An organosilicon resin flame retardant, characterized in that, It is prepared by the preparation method of the organosilicon resin flame retardant according to any one of claims 1 to 8.

Images