Silicon-phosphorus-containing macromolecular flame retardant, flame-retardant low-dielectric polycarbonate containing flame retardant and preparation method of flame-retardant low-dielectric polycarbonate

Abstract

The invention provides a silicon-phosphorus-containing macromolecular flame retardant, flame-retardant low-dielectric polycarbonate containing the flame retardant and a preparation method of the flame-retardant low-dielectric polycarbonate. The preparation method comprises the following steps: mixing and dissolving dichloromethane, triethylamine, bisphenol containing an R structure and bis (aminopropyl)-terminated siloxane to prepare a solution A; dissolving isophthaloyl dichloride and / or paraphthaloyl dichloride and phenylphosphoryl dichloride in dichloromethane to prepare a solution B; dropwise adding the solution B into the solution A, stirring and reacting, and then carrying out end capping treatment to obtain the silicon-phosphorus-containing macromolecular flame retardant. The flame-retardant low-dielectric polycarbonate containing the flame retardant has the advantages of high flame retardance, low dielectric constant and low loss, can meet the flame-retardant requirement of UL 94V-0 level under the condition that the thickness is 0.8-3.2 mm, and belongs to a halogen-free flame-retardant environment-friendly high polymer material.

Description

Technical Field

[0001] This invention belongs to the technical field of organosilicon-phosphorus flame retardants and polycarbonate materials, and relates to a silicon-phosphorus macromolecular flame retardant and a flame-retardant low-dielectric polycarbonate containing the flame retardant and its preparation method. Specifically, it relates to a silicon-phosphorus macromolecular flame retardant, its preparation method and application, and a flame-retardant low-dielectric polycarbonate containing the silicon-phosphorus macromolecular flame retardant, its preparation method and application. Background Technology

[0002] Polycarbonate (PC) is a thermoplastic engineering plastic with excellent mechanical properties and transparency, and it has important applications in fields such as electronics, electrical engineering, and rail transportation.

[0003] With the continuous upgrading of safety standards and the gradual expansion of material application scenarios, the market has set more stringent standards for the flame retardancy of polycarbonate materials. These materials often require the addition of flame retardants to achieve the expected flame retardancy level. Currently, there is a wide variety of conventional flame retardants suitable for polycarbonate, but each category has obvious shortcomings: traditional brominated flame retardants, although possessing strong flame retardant efficacy, have limited application due to their potential bioaccumulation; low-molecular-weight phosphate flame retardants, while being halogen-free and environmentally friendly products, suffer from problems such as volatility and reduced heat resistance of the polycarbonate matrix; sulfonate flame retardants, although catalyzing the formation of a char layer in PC during combustion while maintaining good transparency, have poor hydrolysis resistance, and their flame retardant effect is prone to failure with long-term use. In addition, the addition of conventional flame retardants often leads to a decrease in core mechanical properties of polycarbonate materials, such as impact strength and tensile strength.

[0004] Therefore, the development of polycarbonate materials that possess both high flame retardant properties and excellent mechanical properties has become an important research direction in related fields and has significant practical value. Summary of the Invention

[0005] To address the problems in the prior art, this invention provides a silicon-phosphorus macromolecular flame retardant, a flame-retardant low-dielectric polycarbonate containing the flame retardant, and a method for preparing the same. The flame-retardant low-dielectric polycarbonate containing the flame retardant has the advantages of high flame retardancy, low dielectric constant, and low loss. It can meet the UL 94V-0 flame retardant requirements with a thickness of 0.8–3.2 mm, and is also a halogen-free, flame-retardant, environmentally friendly polymer material.

[0006] To achieve the above objectives, the present invention employs a technical solution consisting of the following technical measures.

[0007] In one aspect, the present invention provides a silicon-phosphorus macromolecular flame retardant, which is composed of compounds represented by the following chemical structural formula:

[0008]

[0009] In the formula, m is an integer in the range of 60 to 90, n is an integer in the range of 50 to 100, and q is an integer in the range of 1 to 40; To represent at least one of the p-benzene or m-benzene structures;

[0010] R represents at least one of the following structures:

[0011]

[0012] Wherein, X is any one of oxygen atom, methylamino group, and benimino group;

[0013] R1 to R3 are any one of hydrogen atoms or methyl groups;

[0014] R4 can be any one of hydrogen, methyl, or phenyl.

[0015] In the above chemical structural formula, "---" indicates the position where the chemical bond is connected.

[0016] On the other hand, the present invention also provides a method for preparing the above-mentioned silicon-phosphorus macromolecular flame retardant, which mainly includes the following steps:

[0017] (1) Add 250-300 mL of dichloromethane, 25-30 mL of triethylamine, 0.06-0.09 mol of bisphenol containing R structure and 0.01-0.04 mol of diaminopropyl-terminated siloxane to a reaction vessel, stir until the solid compound is completely dissolved, and prepare solution A;

[0018] Wherein, the R-containing bisphenol is at least one of the compounds represented by the following chemical structural formulas:

[0019]

[0020]

[0021] (2) Dissolve 0.05–0.1 mol isophthaloyl chloride and / or terephthaloyl chloride and 0–0.05 mol phenylphosphine dichloride in 200–300 mL of dichloromethane to prepare solution B;

[0022] (3) Add liquid B dropwise to liquid A at an ambient temperature of -5 to -3℃ while stirring. After the addition is complete, continue stirring at an ambient temperature of -5 to -3℃ for 3 to 4 hours. After the time is up, add 0.01 to 0.02 mol of phenol for end-capping treatment.

[0023] After end-capping, the product was washed, purified, and dried sequentially to prepare a silicon-phosphorus macromolecular flame retardant.

[0024] In this article, the bisphenols containing the R structure mentioned in step (1) are all small molecule bisphenol compounds that have been publicly disclosed, and can be obtained commercially or made by referring to textbooks / existing technical literature.

[0025] In this article, the diaminopropyl-terminated siloxane described in step (1), CAS: 106214-84-0, is commercially available.

[0026] In one of the technical solutions, the addition of 0.01 to 0.02 mol of phenol for end-capping treatment in step (3) is preferably achieved by dissolving 0.01 to 0.02 mol of phenol in 50 to 100 mL of dichloromethane, then adding it dropwise, and continuing to stir and react at an ambient temperature of -5 to -3°C for 10 to 30 minutes.

[0027] In this document, the stirring, dripping, washing, purification, and drying processes all follow conventional principles in chemical processes, and those skilled in the art can perform the specific operations based on common knowledge.

[0028] In one of the technical solutions, the purification in step (3) is carried out by adding anhydrous ethanol to precipitate the product.

[0029] In one of the technical solutions, the drying in step (3) is performed at a temperature of 80-110°C for 6-7 hours.

[0030] In another aspect, the present invention also provides a flame-retardant low-dielectric polycarbonate containing the above-mentioned silicon-phosphorus macromolecular flame retardant, wherein the raw materials mainly include, by weight parts:

[0031] 68-89 parts of bisphenol A type polycarbonate resin

[0032] 10-30 parts of silicon-phosphorus macromolecular flame retardant

[0033] And conventional antioxidants.

[0034] In this document, the bisphenol A type polycarbonate resin is a conventional matrix raw material for polycarbonate. Those skilled in the art can select a suitable bisphenol A type polycarbonate resin based on common knowledge or specific needs.

[0035] In one of the technical solutions, the bisphenol A type polycarbonate resin is preferably a bisphenol A type polycarbonate resin with a relative molecular weight of 16,000 to 18,000.

[0036] In this document, the antioxidants mentioned are conventional additives for polycarbonate. Those skilled in the art can select appropriate antioxidants based on common knowledge or specific needs.

[0037] To better illustrate the present invention and provide a reference technical solution, the antioxidant includes at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010), 4,4'-bis(α,α-dimethylbenzyl)diphenylamine (NAUGARD 445), bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis(2,4-dicumylphenyl) diphosphite (THP-24), and polypropylene glycol phenyl phosphite (DHOP); the amount of the antioxidant added is 1 to 2 parts.

[0038] In one technical solution, other conventional additives may be added to the raw materials. These other conventional additives are functional additives / processing aids commonly added to polycarbonate. Those skilled in the art can refer to conventional selections in existing processes or functional additives / processing aids used as described in existing literature in the field, such as anti-aging agents, coupling agents, mildew inhibitors, pigments, and other conventional additives. The amount of the above-mentioned other conventional additives added shall be in accordance with their instructions for use / conventional process selection / existing literature descriptions.

[0039] Generally, the preparation method of the above-mentioned flame-retardant low-dielectric polycarbonate can be directly referred to the preparation method of polycarbonate materials in the prior art, such as preparation by twin-screw melt extrusion and granulation; the specific preparation process steps / parameters can be based on the conventional process method of the selected bisphenol A type polycarbonate resin when preparing polycarbonate materials.

[0040] The present invention has the following advantages:

[0041] 1. This invention provides a silicon-phosphorus macromolecular flame retardant, a flame-retardant low-dielectric polycarbonate containing the flame retardant, and a method for preparing the same. The flame-retardant low-dielectric polycarbonate containing the flame retardant has the advantages of high flame retardancy, low dielectric constant and low loss. It can meet the UL 94V-0 flame retardant requirements with a thickness of 0.8 to 3.2 mm, and is also a halogen-free flame-retardant environmentally friendly polymer material.

[0042] 2. The silicon-phosphorus macromolecular flame retardant and the flame-retardant low-dielectric polycarbonate containing the flame retardant provided by the present invention are both halogen-free materials and are environmentally friendly.

[0043] 3. The process of this invention is simple to operate, easy to control and industrialize, and convenient for industrial production. Attached Figure Description

[0044] Figure 1 The image shows the hydrogen nuclear magnetic resonance spectrum of the silicon-phosphorus macromolecular flame retardant prepared in Example 1 of this invention.

[0045] Figure 2The image shows the hydrogen nuclear magnetic resonance spectrum of the silicon-phosphorus macromolecular flame retardant prepared in Example 2 of this invention.

[0046] Figure 3 The image shows the hydrogen nuclear magnetic resonance spectrum of the silicon-phosphorus macromolecular flame retardant prepared in Example 3 of this invention.

[0047] Figure 4 The image shows the hydrogen nuclear magnetic resonance spectrum of the silicon-phosphorus macromolecular flame retardant prepared in Example 4 of this invention.

[0048] Figure 5 The graphs show the comparative results of the heat release rate tests of the samples prepared in Examples 1-5 and the comparative examples of this invention.

[0049] Figure 6 This is a summary and comparison chart of the vertical combustion test results of the samples prepared in Examples 1-5 and the comparative examples of the present invention with a thickness of 3.2 mm. Detailed Implementation

[0050] To further understand the present invention, preferred embodiments are described below with reference to examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims. Those skilled in the art can refer to the content of this document to appropriately improve the process parameters. In particular, it should be noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included within the scope of the present invention. The methods and applications of the present invention have been described through preferred embodiments, and those skilled in the art can obviously make modifications or appropriate changes and combinations to the methods and applications described herein without departing from the content, spirit and scope of the present invention to realize and apply the technology of the present invention. Although it is believed that those skilled in the art will fully understand the following terms, the following definitions are set forth to help illustrate the subject matter disclosed in the present invention.

[0051] In one aspect, the present invention provides a silicon-phosphorus macromolecular flame retardant, which is composed of compounds represented by the following chemical structural formula:

[0052]

[0053] In the formula, m is an integer in the range of 60 to 90, n is an integer in the range of 50 to 100, and q is an integer in the range of 1 to 40; To represent at least one of the p-benzene or m-benzene structures;

[0054] R represents at least one of the following structures:

[0055]

[0056] Wherein, X is any one of oxygen atom, methylamino group, and benimino group;

[0057] R1 to R3 are any one of hydrogen atoms or methyl groups;

[0058] R4 can be any one of hydrogen, methyl, or phenyl.

[0059] In the above chemical structural formula, "---" indicates the position where the chemical bond is connected.

[0060] On the other hand, the present invention also provides a method for preparing the above-mentioned silicon-phosphorus macromolecular flame retardant, which mainly includes the following steps:

[0061] (1) Add 250-300 mL of dichloromethane, 25-30 mL of triethylamine, 0.06-0.09 mol of bisphenol containing R structure and 0.01-0.04 mol of diaminopropyl-terminated siloxane to a reaction vessel, stir until the solid compound is completely dissolved, and prepare solution A;

[0062] Wherein, the R-containing bisphenol is at least one of the compounds represented by the following chemical structural formulas:

[0063]

[0064] (2) Dissolve 0.05–0.1 mol isophthaloyl chloride and / or terephthaloyl chloride and 0–0.05 mol phenylphosphine dichloride in 200–300 mL of dichloromethane to prepare solution B;

[0065] (3) Add liquid B dropwise to liquid A at an ambient temperature of -5 to -3℃ while stirring. After the addition is complete, continue stirring at an ambient temperature of -5 to -3℃ for 3 to 4 hours. After the time is up, add 0.01 to 0.02 mol of phenol for end-capping treatment.

[0066] After end-capping, the product was washed, purified, and dried sequentially to prepare a silicon-phosphorus macromolecular flame retardant.

[0067] In this article, the bisphenols containing the R structure mentioned in step (1) are all small molecule bisphenol compounds that have been publicly disclosed, and can be obtained commercially or made by referring to textbooks / existing technical literature.

[0068] In this article, the diaminopropyl-terminated siloxane described in step (1), CAS: 106214-84-0, is commercially available.

[0069] In one embodiment, the addition of 0.01 to 0.02 mol of phenol for end-capping treatment in step (3) is preferably achieved by dissolving 0.01 to 0.02 mol of phenol in 50 to 100 mL of dichloromethane, then adding it dropwise, and continuing to stir the reaction at an ambient temperature of -5 to -3°C for 10 to 30 minutes.

[0070] In this document, the stirring, dripping, washing, purification, and drying processes all follow conventional principles in chemical processes, and those skilled in the art can perform the specific operations based on common knowledge.

[0071] In one embodiment, the purification in step (3) is performed by adding anhydrous ethanol to precipitate the product.

[0072] In one embodiment, the drying in step (3) is performed at a temperature of 80–110°C for 6–7 hours.

[0073] In another aspect, the present invention also provides a flame-retardant low-dielectric polycarbonate containing the above-mentioned silicon-phosphorus macromolecular flame retardant, wherein the raw materials mainly include, by weight parts:

[0074] 68-89 parts of bisphenol A type polycarbonate resin

[0075] 10-30 parts of silicon-phosphorus macromolecular flame retardant

[0076] And conventional antioxidants.

[0077] In this document, the bisphenol A type polycarbonate resin is a conventional matrix raw material for polycarbonate. Those skilled in the art can select a suitable bisphenol A type polycarbonate resin based on common knowledge or specific needs.

[0078] In one embodiment, the bisphenol A type polycarbonate resin is preferably a bisphenol A type polycarbonate resin with a relative molecular weight of 16,000 to 18,000.

[0079] In this document, the antioxidants mentioned are conventional additives for polycarbonate. Those skilled in the art can select appropriate antioxidants based on common knowledge or specific needs.

[0080] To better illustrate the present invention and provide a reference embodiment, the antioxidant includes at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010), 4,4'-bis(α,α-dimethylbenzyl)diphenylamine (NAUGARD 445), bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis(2,4-dicumylphenyl) diphosphite (THP-24), and polypropylene glycol phenyl phosphite (DHOP); the amount of the antioxidant added is 1 to 2 parts.

[0081] In one embodiment, other conventional additives may be added to the raw materials. These other conventional additives are functional additives / processing aids commonly added to polycarbonate. Those skilled in the art can refer to conventional selections in existing processes or functional additives / processing aids used as described in existing literature, such as anti-aging agents, coupling agents, mildew inhibitors, pigments, and other conventional additives. The amount of the above-mentioned other conventional additives added shall be in accordance with their instructions for use / conventional process selection / existing literature.

[0082] Generally, the preparation method of the above-mentioned flame-retardant low-dielectric polycarbonate can be directly referred to the preparation method of polycarbonate materials in the prior art, such as preparation by twin-screw melt extrusion and granulation; the specific preparation process steps / parameters can be based on the conventional process method of the selected bisphenol A type polycarbonate resin when preparing polycarbonate materials.

[0083] The present application will be further explained in detail below with reference to embodiments. However, those skilled in the art should understand that these embodiments are provided for illustrative purposes only and are not intended to limit the present application.

[0084] Example

[0085] The embodiments of this application will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be construed as limiting the scope of this application. Unless otherwise specified, specific conditions in the examples are performed under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used without specified manufacturers are all commercially available conventional products. Unless otherwise indicated, all quantities listed are described as a weight percentage of the total weight. This application should not be construed as being limited to the specific embodiments described.

[0086] 1. Raw materials

[0087] Triethylamine, R-structured bisphenol, antioxidant 1010, isophthaloyl chloride, diaminopropyl-terminated polysiloxane, etc. are all supplied by Anaiji;

[0088] Dichloromethane, anhydrous ethanol, etc., were provided by Chengdu Kelong Chemical Reagent Factory;

[0089] The bisphenol A type polycarbonate resin was provided by Ningbo Zhetie Dafeng Chemical Co., Ltd.

[0090] 2. Testing Methods

[0091] Vertical burning test according to GB / T 2408-2021, heat release rate test according to GB / T 16172-2007, dielectric constant and dielectric loss test at 50MHz frequency according to GB / T 1409-2006, and oxygen index test according to GB / T2406.2-2009.

[0092] Synthesis example 1

[0093] Example 1: A method for preparing a silicon-phosphorus macromolecular flame retardant, specifically including the following steps:

[0094] (1) Add 250 mL of dichloromethane, 30 mL of triethylamine, 0.06 mol of 1,1-bis(4-hydroxyphenyl)cyclohexane and 0.04 mol of diaminopropyl-terminated siloxane to a reaction vessel, stir until the solid compound is completely dissolved, and prepare solution A;

[0095] (2) Dissolve 0.09 mol isophthaloyl chloride and 0.01 mol phenylphosphoyl dichloride in 200 mL of dichloromethane to prepare solution B;

[0096] (3) Add liquid B dropwise to liquid A at an ambient temperature of -5 to -3℃ while stirring. After the addition is complete, continue stirring for 3 to 4 hours. After the time is up, add 0.01 mol of phenol for end-capping treatment.

[0097] After end-capping, the product was washed, purified, and dried sequentially to prepare a silicon-phosphorus macromolecular flame retardant, denoted as SiP-1.

[0098] Based on the proportioning calculations, the chemical structural formula of the silicon-phosphorus macromolecular flame retardant prepared in Synthesis Example 1 is as follows:

[0099]

[0100] Synthesis example 2

[0101] Synthesis Example 2: A method for preparing a silicon-phosphorus macromolecular flame retardant, specifically including the following steps:

[0102] (1) Add 250 mL of dichloromethane, 30 mL of triethylamine, 0.07 mol of 4,4'-(phenylmethylene)diphenol and 0.03 mol of diaminopropyl-terminated siloxane to a reaction vessel, stir until the solid compound is completely dissolved, and prepare solution A;

[0103] (2) Dissolve 0.08 mol isophthaloyl chloride and 0.02 mol phenylphosphoyl dichloride in 300 mL of dichloromethane to prepare solution B;

[0104] (3) Add liquid B dropwise to liquid A at an ambient temperature of -5 to -3℃ while stirring. After the addition is complete, continue stirring for 3 to 4 hours. After the time is up, add 0.01 mol of phenol for end-capping treatment.

[0105] After end-capping, the product was washed, purified, and dried sequentially to prepare a silicon-phosphorus macromolecular flame retardant, denoted as SiP-2.

[0106] Based on the proportioning calculations, the chemical structural formula of the silicon-phosphorus macromolecular flame retardant prepared in Synthesis Example 2 is as follows:

[0107]

[0108] Synthesis example 3

[0109] Synthesis Example 3: A method for preparing a silicon-phosphorus macromolecular flame retardant, specifically including the following steps:

[0110] (1) Add 250 mL of dichloromethane, 30 mL of triethylamine, 0.07 mol of phenolphthalein and 0.03 mol of diaminopropyl-terminated siloxane to a reaction vessel and stir until the solid compound is completely dissolved to prepare solution A.

[0111] (2) Dissolve 0.06 mol isophthaloyl chloride and 0.04 mol phenylphosphoyl dichloride in 200 mL of dichloromethane to prepare solution B;

[0112] (3) Add liquid B dropwise to liquid A at an ambient temperature of -5 to -3℃ while stirring. After the addition is complete, continue stirring for 3 to 4 hours. After the time is up, add 0.01 mol of phenol for end-capping treatment.

[0113] After end-capping, the product was washed, purified, and dried sequentially to prepare a silicon-phosphorus macromolecular flame retardant, denoted as SiP-3.

[0114] Based on the proportioning calculations, the chemical structural formula of the silicon-phosphorus macromolecular flame retardant prepared in Synthesis Example 3 is as follows:

[0115]

[0116] Synthesis example 4

[0117] Synthesis Example 4: A method for preparing a silicon-phosphorus macromolecular flame retardant, specifically including the following steps:

[0118] (1) Add 300 mL of dichloromethane, 30 mL of triethylamine, 0.09 mol of 3,3-bis(4-hydroxyphenyl)-2-phenylprop-1-one, and 0.01 mol of diaminopropyl-terminated siloxane to a reaction vessel, and stir until the solid compound is completely dissolved to prepare solution A.

[0119] (2) Dissolve 0.05 mol isophthaloyl chloride and 0.05 mol phenylphosphoyl dichloride in 200 mL of dichloromethane to prepare solution B;

[0120] (3) Add liquid B dropwise to liquid A at an ambient temperature of -5 to -3℃ while stirring. After the addition is complete, continue stirring for 3 to 4 hours. After the time is up, add 0.01 mol of phenol for end-capping treatment.

[0121] After end-capping, the product was washed, purified, and dried sequentially to prepare a silicon-phosphorus macromolecular flame retardant, denoted as SiP-4.

[0122] Based on the proportioning calculations, the chemical structural formula of the silicon-phosphorus macromolecular flame retardant prepared in Synthesis Example 3 is as follows:

[0123]

[0124] The values ​​of m, n, and q in the chemical structural formulas of the silicon-phosphorus macromolecular flame retardants prepared by synthesis examples 1-4 are shown in Table 1 below:

[0125] Table 1

[0126] serial number m n q SiP-1 60 90 1 SiP-2 70 80 9 SiP-3 80 60 21 SiP-4 90 50 29

[0127] Examples 1-5, Comparative Examples

[0128] Application Examples 1-5 use the silicon-phosphorus macromolecular flame retardants prepared in Synthesis Examples 1-4 as raw material components to prepare flame-retardant low-dielectric polycarbonate. Specifically, bisphenol A type polycarbonate resin, silicon-phosphorus macromolecular flame retardant, and antioxidant are stirred and mixed to obtain a mixture. Then, the mixture is added to a twin-screw extruder and extruded and granulated at a melting temperature of 260°C to prepare flame-retardant low-dielectric polycarbonate plastic samples.

[0129] The comparative example is the polycarbonate plastic sample prepared without the addition of silicon-phosphorus macromolecular flame retardant;

[0130] The raw material ratios and test results, by weight, are shown in Table 2 below:

[0131] Table 2

[0132]

[0133] like Figures 1-4As shown, the results of nuclear magnetic resonance hydrogen spectroscopy indicate the successful synthesis of silicon-phosphorus macromolecular flame retardants. Figure 5 , Figure 6 As can be seen from the test results in Table 2, the samples of the present invention have excellent flame retardant properties and low dielectric constant and dielectric loss, and are suitable for fields such as electronics, electrical engineering and 5G communication.

[0134] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A silicon-phosphorus macromolecular flame retardant, characterized in that... It is composed of compounds represented by the following chemical structural formulas: In the formula, m is an integer in the range of 60 to 90, n is an integer in the range of 50 to 100, and q is an integer in the range of 1 to 40; To represent at least one of the p-benzene or m-benzene structures; R represents at least one of the following structures: Wherein, X is any one of oxygen atom, methylamino group, and benimino group; R1 to R3 are any one of hydrogen atoms or methyl groups; R4 can be any one of hydrogen, methyl, or phenyl.

2. The preparation method of the silicon-phosphorus macromolecular flame retardant according to claim 1, characterized in that... The main steps include: (1) Add 250-300 mL of dichloromethane, 25-30 mL of triethylamine, 0.06-0.09 mol of bisphenol containing R structure and 0.01-0.04 mol of diaminopropyl-terminated siloxane to a reaction vessel, stir until the solid compound is completely dissolved, and prepare solution A; Wherein, the R-containing bisphenol is at least one of the compounds represented by the following chemical structural formulas: (2) Dissolve 0.05-0.1 mol isophthaloyl chloride and / or terephthaloyl chloride and 0-0.05 mol phenylphosphine dichloride in 200-300 mL of dichloromethane to prepare solution B; (3) Add liquid B dropwise to liquid A at an ambient temperature of -5 to -3℃ while stirring. After the addition is complete, continue stirring at an ambient temperature of -5 to -3℃ for 3 to 4 hours. After the time is up, add 0.01 to 0.02 mol of phenol for end-capping treatment. After end-capping, the product was washed, purified, and dried sequentially to prepare a silicon-phosphorus macromolecular flame retardant.

3. The preparation method according to claim 2, characterized in that: The addition of 0.01 to 0.02 mol of phenol for end-capping in step (3) involves dissolving 0.01 to 0.02 mol of phenol in 50 to 100 mL of dichloromethane, then adding it dropwise, and continuing to stir the reaction at an ambient temperature of -5 to -3°C for 10 to 30 minutes.

4. A flame-retardant low-dielectric polycarbonate containing the silicon-phosphorus macromolecular flame retardant of claim 1, characterized in that... Its main raw materials, by weight, include: 68-89 parts of bisphenol A type polycarbonate resin 10-30 parts of silicon-phosphorus macromolecular flame retardant And conventional antioxidants.

5. The flame-retardant low-dielectric polycarbonate according to claim 4, characterized in that: The bisphenol A type polycarbonate resin is selected from bisphenol A type polycarbonate resins with a relative molecular weight of 16,000 to 18,000.

6. The flame-retardant low-dielectric polycarbonate according to claim 4, characterized in that: The antioxidant includes at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 4,4'-bis(α,α-dimethylbenzyl)diphenylamine, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis(2,4-dicumylphenyl)diphosphite, and polypropylene glycol phenyl phosphite; the amount of the antioxidant added is 1 to 2 parts.

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