Platinum flame retardant for silicone rubber and preparation method thereof

Abstract

The invention belongs to the technical field of catalysts, and particularly discloses a platinum flame retardant for silicone rubber and a preparation method thereof.The platinum flame retardant comprises the following raw materials in parts by weight: an allyl phenol compound, an organic solvent, alkali, PCl3, a silane coupling agent SM1, AIBN, alkoxy hydrosilane SM2, aluminum hydroxide powder, chloroplatinic acid, isopropanol, sodium bicarbonate, 1, 2-propylene glycol and a catalyst. The organic solvent is 1, 2, 3-divinyl tetramethyl disiloxane and alcohol. The preparation method comprises the following steps: firstly, coupling a sulfydryl-containing silane coupling agent, alkoxy hydrosilanes and phosphite ester, then modifying aluminum hydroxide to prepare a phosphine-modified silane coupling agent SG-1, then carrying out ligand exchange on the SG-1 and a Karst catalyst to prepare a single-component platinum catalyst SG-2, and finally, preparing the single-component platinum catalyst SG-2. The complex can be used as an effective catalyst for a hydrosilylation reaction, does not need to add an additional inhibitor during use, is used in the field of silicone rubber, and has excellent flame retardance.

Description

Technical Field

[0001] The invention relates to the technical field of catalysts, in particular to a platinum flame retardant for silicone rubber and a preparation method thereof. Background Art

[0002] Silicone rubber has excellent properties such as high and low temperature resistance and oxygen resistance, but it is flammable, which limits its further development in the fields of electronics, electrical, automotive, and aviation. Therefore, the preparation of flame-retardant silicone rubber is of great research significance. For the flame retardancy of silicone rubber, the most widely used halogen-free flame retardant on the market is currently aluminum hydroxide, which is usually used in conjunction with a platinum catalyst for flame retardancy. However, the following problems may occur in this process:

[0003] 1) The most widely used platinum catalyst is the Custer catalyst, but it is unstable in high temperature processes, which seriously affects its flame retardant properties. Therefore, it is necessary to introduce acetylenic alcohols, phosphites, and benzotriazole inhibitors to protect the catalyst;

[0004] 2) Aluminum hydroxide and platinum catalyst can synergistically flame retardant when physically mixed. The platinum catalyst has poor dispersion performance in aluminum hydroxide and is prone to agglomeration, resulting in reduced platinum utilization.

[0005] In view of the shortcomings of the prior art, the present invention provides a platinum flame retardant for silicone rubber and a preparation method thereof, so that aluminum hydroxide modified by a silane coupling agent and platinum are chemically combined, which not only improves the utilization rate of platinum, but also introduces a phosphite type ligand to improve the stability of platinum. This new type of platinum catalyst has excellent flame retardant properties when applied to silicone rubber. Summary of the invention

[0006] To solve the above technical problems, according to one aspect of the present invention, the present invention provides the following technical solutions:

[0007] A platinum flame retardant for silicone rubber comprises raw materials, which include, by weight: 4-6 parts of 2-allylphenol compounds, 100-160 parts of organic solvents, 1-2 parts of alkali, 34-6 parts of PCl, 13-7 parts of silane coupling agent SM, 0.4-0.6 parts of AIBN, 23-7 parts of alkoxyhydrosilane SM, 4-8 parts of aluminum hydroxide powder, 18-22 parts of chloroplatinic acid, 250-270 parts of isopropanol, 25-27 parts of sodium bicarbonate, 80-100 parts of 1,3-divinyltetramethyldisiloxane, and 110-130 parts of alcohol.

[0008] A method for preparing a platinum flame retardant for silicone rubber comprises the following specific steps:

[0009] Step 1, synthesis of S1: dissolve 2-allylphenol compound in an organic solvent, slowly add alkali at zero degrees, stir at zero degrees for 30 minutes, then add PCl3, heat and react for three hours, monitor the reaction of the raw materials, quench the reaction, cool and filter, and obtain the target product S1, as shown in the following structural formula:

[0010]

[0011] Step 2, synthesis of S2: The synthesis of S2 includes the following methods:

[0012] Method 1: Add S1 and silane coupling agent SM1 to an organic solvent, then add AIBN, heat and react for three hours, monitor the reaction of the raw materials, cool, filter and wash with alcohol to obtain the target product S2;

[0013] Method 2: S1 and alkoxyhydrosilane SM2 are added to an organic solvent, and then a Custer catalyst is added, and the temperature is raised to react for two hours. After monitoring the reaction of the raw materials, the target product S2 can be obtained after cooling, filtering, and washing with alcohol;

[0014] Step 3, synthesis of SG-1: take the dried aluminum hydroxide powder, put it into a universal grinder, drop S2 into it, and grind it in the grinder for ten minutes to obtain aluminum hydroxide SG-1 modified with a silane coupling agent;

[0015] Step 4, synthesis of Custer catalyst: add chloroplatinic acid, isopropanol, sodium bicarbonate and 1,3-divinyltetramethyldisiloxane into a reaction kettle, and react at 70° C. for one hour, then filter the mixture, and concentrate under reduced pressure to obtain Custer catalyst;

[0016] Step 5, synthesis of SG-2: Add the Castel catalyst, SG-1 and an organic solvent into a flask, stir the reaction under N2, and then monitor the reaction progress using GCMS. Thereafter, add alcohol to the obtained precipitate, stir and mix, filter, and wash the precipitate with alcohol, and then dry to obtain the target SG-2.

[0017] As a preferred embodiment of the method for preparing a platinum flame retardant for silicone rubber according to the present invention, the 2-allylphenol compound refers to a compound shown in the following structure:

[0018]

[0019] Wherein, R1 is an alkyl group having 1 to 6 carbon atoms.

[0020] As a preferred embodiment of the method for preparing a platinum flame retardant for silicone rubber according to the present invention, the organic solvent is a mixture of one or more of toluene, tetrahydrofuran, N,N-dimethylformamide, dichloromethane and petroleum ether.

[0021] As a preferred embodiment of the method for preparing a platinum flame retardant for silicone rubber according to the present invention, the base is a mixture of one or more of sodium hydride, triethylamine, sodium carbonate, sodium bicarbonate, sodium hydroxide and potassium hydroxide.

[0022] As a preferred embodiment of the method for preparing a platinum flame retardant for silicone rubber according to the present invention, the heating temperature in step one is 50-90°C, and the heating temperature in step two is 50-90°C.

[0023] As a preferred embodiment of the method for preparing a platinum flame retardant for silicone rubber described in the present invention, the silane coupling agent SM1 is a mixture of one or more of 3-mercaptopropyltriethoxysilane, mercaptopropyltrimethoxysilane and 2-mercaptoethyltriethoxysilane.

[0024] As a preferred embodiment of the method for preparing a platinum flame retardant for silicone rubber according to the present invention, the alkoxyhydrogensilane SM2 is a mixture of one or more of trimethoxyhydrogensilane and triethoxyhydrogensilane.

[0025] As a preferred embodiment of the method for preparing a platinum flame retardant for silicone rubber according to the present invention, the alcohol is a mixture of one or more of methanol, ethanol and isopropanol.

[0026] Compared with existing technologies:

[0027] The preparation method provided by the present invention utilizes unsaturated phosphite to react with a sulfur-containing hydrocarbon silane coupling agent or an alkoxyhydrogen silane to prepare a novel silane coupling agent S2, then modifies aluminum hydroxide to prepare a novel silane coupling agent-modified aluminum hydroxide SG-1, and then uses SG-1 and a Custer catalyst to prepare a single-component platinum catalyst SG-2 through ligand exchange. The single-component catalyst is suitable for a hydrosilylation reaction, and the electronic effect and steric effect of phosphine can be utilized to achieve that the single-component catalyst has a low catalyst activity at room temperature, and can quickly catalyze the hydrosilylation reaction when the temperature rises; in addition, the aluminum hydroxide modified by the novel silane coupling agent is chemically combined with platinum to prepare a silicone rubber product with excellent flame retardant properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The schematic diagram is a process diagram of the synthesis of the phosphine-modified silane coupling agent of the present invention and the ligand exchange. DETAILED DESCRIPTION

[0029] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below.

[0030] Embodiment 1:

[0031] The present invention provides a method for preparing a platinum flame retardant for silicone rubber, comprising the following specific steps:

[0032] Step 1: Dissolve 5 g of 2-allylphenol in 50 mL of tetrahydrofuran, slowly add 1.5 g of NaH at zero degrees Celsius, stir at zero degrees Celsius for 30 minutes, then add 5 g of PCl3, react at 60°C for three hours, monitor the completion of the reaction of the raw materials, quench the reaction, cool and filter, wash with ethanol, and concentrate under reduced pressure to obtain 15 g of the target product S1;

[0033] Step 2: Add 2g S1 and 6g 3-mercaptopropyltriethoxysilane to 50mL toluene, then add 0.5g AIBN, react at 60°C for three hours, monitor the completion of the reaction of the raw materials, cool, filter, and wash with ethanol to obtain the target product 7g S2;

[0034] Step 3: Take 50g of aluminum hydroxide powder (specific surface area 100m2) dried in an oven at 120℃ 2 / g), put it into a universal grinder, add 5.7 g S2 in batches, and grind it in the grinder for 20 minutes to obtain 55.7 g 3-mercaptopropyltriethoxysilane-modified aluminum hydroxide SG-1A;

[0035] Step 4: preheat the reactor to 70°C, adjust the speed to a suitable level, add 20g of chloroplatinic acid, 260mL of isopropanol, 26g of sodium bicarbonate, and 90mL of 1,3-divinyltetramethyldisiloxane, react at 70°C for one hour, cool to room temperature, filter the mixture three times, and concentrate the filtrate under reduced pressure to remove the solvent and other volatile impurities to obtain 100g of Custer catalyst, which is diluted to 5000ppm for use in the next step;

[0036] Step 5: Add 20g of Custer catalyst (equivalent to 512.8umol), 5.7g of SG-1A, and 20mL of toluene solution into a three-necked round-bottom flask and react completely at 60°C under N2; add isopropanol to the obtained precipitate, stir and mix, and then filter. Wash the precipitate three times with isopropanol, and concentrate and dry under vacuum to obtain the target product 5g SG-2A.

[0037] Embodiment 2:

[0038] The present invention provides a method for preparing a platinum flame retardant for silicone rubber, comprising the following specific steps:

[0039] Step 1: Dissolve 5 g of 2-allylphenol in 50 mL of tetrahydrofuran, slowly add 1.5 g of NaH at zero degrees Celsius, stir at zero degrees Celsius for 30 minutes, then add 5 g of PCl3, react at 60°C for three hours, monitor the completion of the reaction of the raw materials, quench the reaction, cool and filter, wash with ethanol, and concentrate under reduced pressure to obtain 15 g of the target product S1;

[0040] Step 2: Add 2 g S1 and 6 g mercaptopropyltrimethoxysilane to 50 mL toluene, then add 0.5 g AIBN, react at 60 ° C for three hours, monitor the completion of the reaction of the raw materials, cool, filter, and wash with ethanol to obtain the target product 6.9 g S2;

[0041] Step 3: Take 50g of aluminum hydroxide powder (specific surface area 100m2) dried in an oven at 120℃ 2 / g), put it into a universal grinder, add 5.1 g S2 in batches, and grind it in the grinder for 20 minutes to obtain 55.1 g of mercaptopropyltrimethoxysilane-modified aluminum hydroxide SG-1B;

[0042] Step 4: preheat the reactor to 70°C, adjust the speed to a suitable level, add 20g of chloroplatinic acid, 260mL of isopropanol, 26g of sodium bicarbonate, and 90mL of 1,3-divinyltetramethyldisiloxane, react at 70°C for one hour, cool to room temperature, filter the mixture three times, and concentrate the filtrate under reduced pressure to remove the solvent and other volatile impurities to obtain 100g of Custer catalyst, which is diluted to 5000ppm for use in the next step;

[0043] Step 5: Add 20g of Custer catalyst (equivalent to 512.8umol), 5.6g of SG-1B, and 20mL of toluene solution into a three-necked round-bottom flask and react completely at 60°C under N2; add isopropanol to the obtained precipitate, stir and mix, and then filter. Wash the precipitate three times with isopropanol, and concentrate and dry under vacuum to obtain the target product 5.1g SG-2B.

[0044] Embodiment 3:

[0045] The present invention provides a method for preparing a platinum flame retardant for silicone rubber, comprising the following specific steps:

[0046] Step 1: Dissolve 5 g of 2-allylphenol in 50 mL of tetrahydrofuran, slowly add 1.5 g of NaH at zero degrees Celsius, stir at zero degrees Celsius for 30 minutes, then add 5 g of PCl3, react at 60°C for three hours, monitor the completion of the reaction of the raw materials, quench the reaction, cool and filter, wash with ethanol, and concentrate under reduced pressure to obtain 15 g of the target product S1;

[0047] Step 2: Add 2 g S1 and 6 g 2-mercaptoethyltriethoxysilane to 50 mL toluene, then add 0.5 g AIBN, react at 60 ° C for three hours, monitor the completion of the reaction of the raw materials, cool, filter, and wash with ethanol to obtain the target product 7.5 g S2;

[0048] Step 3: Take 50g of aluminum hydroxide powder (specific surface area 100m2) dried in an oven at 120℃ 2 / g), put it into a universal grinder, add 4.9 g S2 in batches, and grind it in the grinder for 20 minutes to obtain 54.9 g 2-mercaptoethyltriethoxysilane-modified aluminum hydroxide SG-1C;

[0049] Step 4: preheat the reactor to 70°C, adjust the speed to a suitable level, add 20g of chloroplatinic acid, 260mL of isopropanol, 26g of sodium bicarbonate, and 90mL of 1,3-divinyltetramethyldisiloxane, react at 70°C for one hour, cool to room temperature, filter the mixture three times, and concentrate the filtrate under reduced pressure to remove the solvent and other volatile impurities to obtain 100g of Custer catalyst, which is diluted to 5000ppm for use in the next step;

[0050] Step 5: Add 20g of Custer catalyst (equivalent to 512.8umol), 5.7g of SG-1C, and 20mL of toluene solution into a three-necked round-bottom flask and react completely at 60°C under N2; add isopropanol to the obtained precipitate, stir and mix, and then filter. Wash the precipitate three times with isopropanol, and concentrate and dry under vacuum to obtain the target product 5.0g SG-2C.

[0051] Embodiment 4:

[0052] The present invention provides a method for preparing a platinum flame retardant for silicone rubber, comprising the following specific steps:

[0053] Step 1: Dissolve 5 g of 2-allylphenol in 50 mL of tetrahydrofuran, slowly add 1.5 g of NaH at zero degrees Celsius, stir at zero degrees Celsius for 30 minutes, then add 5 g of PCl3, react at 60°C for three hours, monitor the completion of the reaction of the raw materials, quench the reaction, cool and filter, wash with ethanol, and concentrate under reduced pressure to obtain 15 g of the target product S1;

[0054] Step 2: Add 4g S1 and 3.4g trimethoxysilane to 60mL toluene, then add 1 drop of 0.1M Custer catalyst, react at 80°C for two hours, monitor the completion of the raw material reaction, cool, filter, and wash with methanol to obtain the target product 7.3g S2;

[0055] Step 3: Take 50g of aluminum hydroxide powder (specific surface area 100m2) dried in an oven at 120℃ 2 / g), put it into a universal grinder, add 3.98 g S2 in batches, and grind it in the grinder for 20 minutes to obtain 54.0 g trimethoxysilane-modified aluminum hydroxide SG-1D;

[0056] Step 4: preheat the reactor to 70°C, adjust the speed to a suitable level, add 20g of chloroplatinic acid, 260mL of isopropanol, 26g of sodium bicarbonate, and 90mL of 1,3-divinyltetramethyldisiloxane, react at 70°C for one hour, cool to room temperature, filter the mixture three times, and concentrate the filtrate under reduced pressure to remove the solvent and other volatile impurities to obtain 100g of Custer catalyst, which is diluted to 5000ppm for use in the next step;

[0057] Step 5: Add 20g of Custer catalyst (equivalent to 512.8umol), 5.53g of SG-1D, and 20mL of toluene solution into a three-necked round-bottom flask and react completely at 60°C under N2; add isopropanol to the obtained precipitate, stir and mix, and then filter. Wash the precipitate three times with isopropanol, and concentrate and dry under vacuum to obtain the target product 5.3g SG-2D.

[0058] Embodiment 5:

[0059] The present invention provides a method for preparing a platinum flame retardant for silicone rubber, comprising the following specific steps:

[0060] Step 1: Dissolve 5 g of 2-allylphenol in 50 mL of tetrahydrofuran, slowly add 1.5 g of NaH at zero degrees Celsius, stir at zero degrees Celsius for 30 minutes, then add 5 g of PCl3, react at 60°C for three hours, monitor the completion of the reaction of the raw materials, quench the reaction, cool and filter, wash with ethanol, and concentrate under reduced pressure to obtain 15 g of the target product S1;

[0061] Step 2: Add 4 g S1 and 4.6 g triethoxysilane to 80 mL toluene, then add 1 drop of 0.1 M Custer catalyst, react at 80 ° C for two hours, monitor the completion of the reaction of the raw materials, cool, filter, and wash with methanol to obtain the target product 8.5 g S2;

[0062] Step 3: Take 50g of aluminum hydroxide powder (specific surface area 100m2) dried in an oven at 120℃ 2 / g), put it into a universal grinder, add 4.61g S2 in batches, and grind it in the grinder for 20 minutes to obtain 54.0g triethoxysilane-modified aluminum hydroxide SG-1E;

[0063] Step 4: preheat the reactor to 70°C, adjust the speed to a suitable level, add 20g of chloroplatinic acid, 260mL of isopropanol, 26g of sodium bicarbonate, and 90mL of 1,3-divinyltetramethyldisiloxane, react at 70°C for one hour, cool to room temperature, filter the mixture three times, and concentrate the filtrate under reduced pressure to remove the solvent and other volatile impurities to obtain 100g of Custer catalyst, which is diluted to 5000ppm for use in the next step;

[0064] Step 5: Add 20 g of Custer catalyst (equivalent to 512.8 ummol), 5.60 g of SG-1E, and 20 mL of toluene solution into a three-necked round-bottom flask and react completely at 60 ° C under N2; add isopropanol to the obtained precipitate, stir and mix, and then filter. Wash the precipitate three times with isopropanol, and concentrate and dry under vacuum to obtain the target product 5.5 g SG-2E.

[0065] Comparative Example 1:

[0066] The preparation process is similar to that of Example 1, except that step (3) is omitted, and S2 obtained in step 2 is directly subjected to ligand exchange with a Custer catalyst to prepare S2-2A'.

[0067] Comparative Example 2:

[0068] The preparation process is similar to that of Example 4, except that step (3) is omitted, and S2 obtained in step 2 is directly subjected to ligand exchange with a Custer catalyst to prepare S2-2D'.

[0069] a. Test of high temperature vulcanization performance

[0070] Take 100g of methyl vinyl solid silicone rubber HS-2161 (Hesheng Silicon Industry Co., Ltd.), add 2.4g of hydrogenated silicone oil (hydrogen content 0.75%) and 5g of the above-prepared catalysts SG-2A, SG-2B, SG-2C, SG-2D, SG-2E, SG-2A', SG-2D' in turn, and make triangle packages 10 times in an open mixing mill to obtain the final rubber mixture, and vulcanize and mold at a temperature of 160°C for 3min to obtain silicone rubber samples A, B, C, D, E, A', D'.

[0071] Table 1 below shows the vulcanization results of silicone rubber samples A, B, C, D, E, A', and D' prepared in Examples and Comparative Examples.

[0072] Table 1 High temperature catalytic results of examples and comparative examples

[0073]

[0074] As can be seen from Table 1, the catalysts SG-2A, SG-2B, SG-2C, SG-2D, and SG-2E prepared by Examples 1, 2, 3, 4, and 5 have similar vulcanization effects on the high-temperature catalytic silicone rubber composition as the catalysts SG-2A' and SG-2D' prepared by Comparative Examples 1 and 2, and do not affect the vulcanization performance.

[0075] b. Flame retardant performance test

[0076] The flame retardancy rating of the silicone rubber samples to which the single-component platinum flame retardant of the embodiments and comparative examples was added was determined using the UL94 standard.

[0077] Take 100g of methyl vinyl silicone rubber HS-2161 (Hesheng Silicon Industry Co., Ltd.), add 2.4g of hydrogenated silicone oil (hydrogen content 0.75%) and 5g of the above-prepared catalyst SG-2A, SG-2B, SG-2C, SG-2D, SG-2E, SG-2A', SG-2D' in turn, and make triangle packages 10 times to obtain the final rubber mixture, and vulcanize and mold at a temperature of 160°C for 3min to obtain silicone rubber samples A, B, C, D, E, A', D'. The thickness of the silicone rubber sample is 2mm.

[0078] The flame retardant performance test standard is:

[0079] Limiting oxygen index is tested according to GB / T 10707-2008;

[0080] Vertical burning performance (i.e. flame retardant grade) is tested according to GB / T13488-2008;

[0081] Table 2 below shows the flame retardancy test results of silicone rubber samples A, B, C, D, E, A', and D' prepared using catalysts prepared in Examples and Comparative Examples.

[0082] Table 2 Flame retardant test results of A, B, C, D, E, A', D'

[0083] Sample Limiting oxygen index Vertical combustion performance A 30.9％ UL94V-0 B 30.3％ UL94V-0 C 29.8％ UL94V-1 D 30.5％ UL94V-0 E 30.0％ UL94V-0 A’ 25％ UL94V-2 D’ 23％ UL94V-2

[0084] As can be seen from Table 2, the flame retardant grades of the catalysts SG-2A, SG-2B, SG-2C, SG-2D, and SG-2E prepared by Examples 1, 2, 3, 4, and 5 can reach UL94V-0 and UL94V-1 levels, respectively, while the catalysts SG-2A' and SG-2D' prepared by the comparative examples can only reach UL94V-2 level.

[0085] Based on the above, the synthesis of the phosphine-modified silane coupling agent and the ligand exchange process in the present invention are as follows: Figure 1 shown.

[0086] Although the present invention has been described above with reference to the embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the various features in the embodiments disclosed in the present invention may be used in combination with each other in any manner, and the fact that these combinations are not exhaustively described in this specification is only for the sake of omitting space and saving resources. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A platinum flame retardant for silicone rubber, comprising raw materials, characterized in that: The raw materials include, by weight: 4-6 parts of 2-allylphenol compounds, 100-160 parts of organic solvents, 1-2 parts of alkali, 34-6 parts of PCl, 13-7 parts of silane coupling agent SM, 0.4-0.6 parts of AIBN, 23-7 parts of alkoxyhydrogensilane SM, 4-8 parts of aluminum hydroxide powder, 18-22 parts of chloroplatinic acid, 250-270 parts of isopropanol, 25-27 parts of sodium bicarbonate, 80-100 parts of 1,3-divinyltetramethyldisiloxane, and 110-130 parts of alcohol.

2. A method for preparing a platinum flame retardant for silicone rubber, characterized in that: The specific steps are as follows: Step 1, synthesis of S1: dissolve 2-allylphenol compound in an organic solvent, slowly add alkali at zero degrees, stir at zero degrees for 30 minutes, then add PCl3, heat and react for three hours, monitor the reaction of the raw materials, quench the reaction, cool and filter, and obtain the target product S1, as shown in the following structural formula: Step 2, synthesis of S2: The synthesis of S2 includes the following methods: Method 1: Add S1 and silane coupling agent SM1 to an organic solvent, then add AIBN, heat and react for three hours, monitor the reaction of the raw materials, cool, filter and wash with alcohol to obtain the target product S2; Method 2: S1 and alkoxyhydrosilane SM2 are added to an organic solvent, and then a Custer catalyst is added, and the temperature is raised to react for two hours. After monitoring the reaction of the raw materials, the target product S2 can be obtained after cooling, filtering, and washing with alcohol; Step 3, synthesis of SG-1: take the dried aluminum hydroxide powder, put it into a universal grinder, drop S2 into it, and grind it in the grinder for ten minutes to obtain aluminum hydroxide SG-1 modified with a silane coupling agent; Step 4, synthesis of Custer catalyst: add chloroplatinic acid, isopropanol, sodium bicarbonate and 1,3-divinyltetramethyldisiloxane into a reaction kettle, and react at 70° C. for one hour, then filter the mixture, and concentrate under reduced pressure to obtain Custer catalyst; Step 5, synthesis of SG-2: Add the Castel catalyst, SG-1 and an organic solvent into a flask, stir the reaction under N2, and then monitor the reaction progress using GCMS. Thereafter, add alcohol to the obtained precipitate, stir and mix, filter, and wash the precipitate with alcohol, and then dry to obtain the target SG-2.

3. The method for preparing a platinum flame retardant for silicone rubber according to claim 2, characterized in that: The 2-allylphenol compound refers to a class of compounds shown in the following structure: Wherein, R1 is an alkyl group having 1 to 6 carbon atoms.

4. The method for preparing a platinum flame retardant for silicone rubber according to claim 2, characterized in that: The organic solvent is a mixture of one or more of toluene, tetrahydrofuran, N,N-dimethylformamide, dichloromethane and petroleum ether.

5. The method for preparing a platinum flame retardant for silicone rubber according to claim 2, characterized in that: The base is one or more mixtures of sodium hydride, triethylamine, sodium carbonate, sodium bicarbonate, sodium hydroxide and potassium hydroxide.

6. The method for preparing a platinum flame retardant for silicone rubber according to claim 2, characterized in that: The heating temperature in the step 1 is 50-90°C, and the heating temperature in the step 2 is 50-90°C.

7. The method for preparing a platinum flame retardant for silicone rubber according to claim 2, characterized in that: The silane coupling agent SM1 is a mixture of one or more of 3-mercaptopropyltriethoxysilane, mercaptopropyltrimethoxysilane and 2-mercaptoethyltriethoxysilane.

8. The method for preparing a platinum flame retardant for silicone rubber according to claim 2, characterized in that: The alkoxyhydrogensilane SM2 is a mixture of one or more of trimethoxyhydrogensilane and triethoxyhydrogensilane.

9. The method for preparing a platinum flame retardant for silicone rubber according to claim 2, characterized in that: The alcohol is a mixture of one or more of methanol, ethanol and isopropanol.

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