Organic silica gel and preparation method thereof

Abstract

The invention provides organic silica gel and a preparation method thereof. The organic silica gel comprises a component A, a component B and boron nitride, the component A is prepared from the following components in parts by mass: 40 to 80 parts of vinyl silicon resin, 30 to 60 parts of vinyl silicone oil, 10 to 20 parts of MQ silicon resin without active hydrogen groups, 1 to 5 parts of vinyl POSS (Polyhedral Oligomeric Silsesquioxane) and 0.01 to 0.1 part of catalyst; the component B is prepared from the following components in parts by mass: 10 to 50 parts of hydrogen-containing silicone oil, 10 to 20 parts of MQ silicon resin, 0 to 5 parts of POSS (Polyhedral Oligomeric Silsesquioxane) without vinyl and 0.01 to 0.1 part of an inhibitor; wherein based on the total mass of the organic silica gel, the mass content of the boron nitride is 0.1%-1%. The organic silica gel at least has the advantages of being environmentally friendly, excellent in flame retardant property and mechanical property and the like.

Description

Technical Field

[0001] This application relates to the field of silicone materials technology, and in particular to an organosilicon and its preparation method. Background Technology

[0002] Silicone rubber is an elastic polymer with polysiloxane as its main chain. It has high and low temperature resistance, excellent electrical insulation, good chemical stability and biocompatibility, and is widely used in key fields such as electronic packaging, new energy vehicles, aerospace, medical devices and construction.

[0003] The intrinsic molecular structure of polysiloxanes is highly flammable, and when exposed to fire, it will continue to burn and release smoke, posing a fire safety hazard. Therefore, this severely limits the application of silicone rubber in scenarios with extremely high safety requirements, such as battery pack sealing and high-voltage insulation components.

[0004] Currently, flame-retardant modification of silicone rubber mainly relies on the addition of traditional flame retardants. Hydroxide flame retardants such as aluminum hydroxide (ATH) and magnesium hydroxide (MDH) can absorb heat and release water vapor during high-temperature decomposition, thus achieving a flame-retardant effect; however, they also severely degrade the mechanical properties, flexibility, and processing flowability of silicone rubber. Halogenated flame retardants, while having high flame-retardant efficiency, produce toxic and corrosive gases during combustion and are therefore being phased out. Phosphorus-based flame retardants and intumescent flame retardants have problems such as poor compatibility with the matrix, easy migration and precipitation, or reduced heat resistance of the material.

[0005] Therefore, methods for improving the flame retardant properties of silicone rubber still need further optimization. Summary of the Invention

[0006] Based on this, one or more embodiments of this application provide a green and environmentally friendly silicone material with excellent flame retardant and mechanical properties, and a method for preparing the same.

[0007] According to a first aspect of the embodiments of this application, an organosilicon is provided, comprising component A, component B and boron nitride;

[0008] By mass, component A comprises 40-80 parts vinyl silicone resin, 30-60 parts vinyl silicone oil, 10-20 parts MQ silicone resin without active hydrogen groups, 1-5 parts vinyl POSS and 0.01-0.1 parts catalyst;

[0009] By weight, component B comprises 10-50 parts of hydrogen-containing silicone oil, 10-20 parts of MQ silicone resin, 0-5 parts of vinyl-free POSS, and 0.01-0.1 parts of inhibitor;

[0010] The boron nitride content is 0.1% to 1% based on the total mass of the silicone.

[0011] In some embodiments, the boron nitride is silane coupling agent modified boron nitride.

[0012] In some embodiments, the boron nitride has a particle size of 1 μm to 2 μm.

[0013] In some embodiments, the silicone rubber satisfies at least one of the following characteristics:

[0014] (1) The vinyl content in the vinyl silicone resin is 0.9%~1.9% by mass;

[0015] (2) The vinyl content in the vinyl silicone oil is 0.1%~0.5% by mass;

[0016] (3) The viscosity of the vinyl silicone oil is 300 cps to 10000 cps;

[0017] (4) The hydrogen content in the hydrogen-containing silicone oil is 0.1% to 0.5% by mass.

[0018] In some embodiments, the silicone rubber satisfies at least one of the following characteristics:

[0019] (1) In component A, the catalyst includes a platinum complex;

[0020] (2) In the B component, the inhibitor includes one or more of alkynyl alcohol inhibitors and silicone inhibitors.

[0021] According to a second aspect of the embodiments of this application, a method for preparing silicone rubber is provided, comprising the following steps:

[0022] The raw materials are provided according to the aforementioned silicone materials;

[0023] The raw materials for preparing component A are mixed to prepare component A;

[0024] The raw materials for preparing component B are mixed to prepare component B;

[0025] The organosilicon is prepared by mixing the components A and B with the boron nitride and then curing the mixture.

[0026] In some embodiments, before mixing component A, component B and boron nitride, the following steps are further included: sequentially crushing, ultrasonicating and drying the boron nitride.

[0027] In some embodiments, mixing component A, component B, and boron nitride includes the following steps:

[0028] The A component is mixed with the boron nitride and dispersed to prepare a mixed slurry; then the mixed slurry is mixed with the B component.

[0029] In some embodiments, the boron nitride is modified boron nitride, and the modifier of the modified boron nitride includes a silane coupling agent; the content of the silane coupling agent is 0.5% to 5% based on the total mass of the modifier.

[0030] In some embodiments, the curing temperature is 65°C to 75°C and the curing time is 3 to 5 hours.

[0031] Compared with traditional technologies, this application has the following advantages:

[0032] This application enhances the mechanical properties of silicone rubber by adding boron nitride, which is distributed within the polymer network of the silicone rubber, enabling it to withstand stronger external stresses. Simultaneously, boron nitride facilitates rapid heat dissipation within the silicone rubber, reducing the risk of combustion due to localized overheating. Furthermore, under combustion conditions, boron nitride forms a dense insulating layer on the surface of the silicone rubber, isolating it from external oxygen and further reducing the likelihood of subsequent combustion, thereby improving the flame-retardant properties of the silicone rubber. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the specific embodiments of this application, the drawings used in the description of the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0034] Figure 1 A 3D diagram of the thermogravimetric-infrared spectroscopy test results for Comparative Example 1;

[0035] Figure 2 A 3D image of the thermogravimetric-infrared spectroscopy test results of Example 3;

[0036] Figure 3 The peak values ​​of the thermogravimetric infrared spectroscopy test results of Comparative Example 1 and Example 3 at 500℃ are compared.

[0037] Figure 4 The peak intensity variation graphs are the thermogravimetric infrared (TGA) test results of Comparative Example 1 and Example 3 at different times. Detailed Implementation

[0038] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, a detailed description of specific embodiments of this application is provided. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. Unless otherwise specifically stated, all raw materials, reagents, instruments, and equipment used in this application are commercially available or can be prepared by existing methods.

[0040] The terms "and / or," "or / and," and "and / or" as used herein include any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. It should be noted that when at least three items are connected by at least two conjunctions selected from "and / or," "or / and," and "and / or," it should be understood that in this application, the technical solution undoubtedly includes technical solutions connected by "logical AND," and also undoubtedly includes technical solutions connected by "logical OR." For example, "A and / or B" includes three parallel solutions: A, B, and A+B. For example, the technical solution of "A, and / or, B, and / or, C, and / or, D" includes any one of A, B, C, and D (that is, a technical solution that is connected by "logical OR"), as well as any and all combinations of A, B, C, and D, that is, combinations of any two or three of A, B, C, and D, and also combinations of all four of A, B, C, and D (that is, a technical solution that is connected by "logical AND").

[0041] In this application, the terms "multiple", "various", "multiple times", "multi-dimensional", etc., unless otherwise specified, refer to a quantity greater than or equal to 2. For example, "one or more" means one or more than or equal to two.

[0042] The terms “combinations of,” “any combination of,” and “any combination of” used in this article include all suitable combinations of any two or more of the listed items.

[0043] In this document, the term "suitable" as used in phrases such as "suitable combination," "suitable method," and "any suitable method" refers to the ability to implement the technical solution of this application, solve the technical problem of this application, and achieve the expected technical effect of this application.

[0044] In this document, terms such as “preferred,” “better,” “more suitable,” and “ideal” are merely used to describe implementation methods or examples that achieve better results, and should be understood not to limit the scope of protection of this application.

[0045] In this application, terms such as "further," "even further," and "particularly" are used to describe purposes and indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0046] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it means that it is selected from either "with" or "without." If there are multiple "optional" entries in a technical solution, unless otherwise specified, and there are no contradictions or mutual constraints, each "optional" entry shall be independent.

[0047] In this application, the terms "first aspect," "second aspect," "third aspect," "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," "fourth," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0048] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0049] In this application, numerical intervals (i.e., numerical ranges) are involved. Unless otherwise specified, the selected numerical distributions within the aforementioned numerical intervals are considered continuous and include the two endpoints (i.e., the minimum and maximum values) of the numerical range, as well as every value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints. In this document, this is equivalent to directly listing every integer. For example, if t is an integer selected from 1 to 10, it means that t is any integer selected from the group of integers consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10. Furthermore, when multiple ranges are provided to describe features or characteristics, these ranges can be merged. In other words, unless otherwise specified, the ranges disclosed herein should be understood to include any and all subranges to which they are included.

[0050] Unless otherwise specified, the temperature parameters in this application are permitted to be either constant-temperature treatment or variations within a certain temperature range. It should be understood that the constant-temperature treatment allows temperature fluctuations within the precision range of the instrument control, such as ±5℃, ±4℃, ±3℃, ±2℃, or ±1℃.

[0051] In this application, "room temperature" or "normal temperature" generally refers to 4℃~35℃, for example, 20℃±5℃. In some embodiments of this application, "room temperature" or "normal temperature" refers to 10℃~30℃. In some embodiments of this application, "room temperature" or "normal temperature" refers to 20℃~30℃.

[0052] In this application, %(w / w) and wt% both represent weight percentage, %(v / v) refers to volume percentage, and %(w / v) refers to mass-volume percentage.

[0053] Some embodiments of this application provide an organosilicon material, comprising component A, component B, and boron nitride;

[0054] By mass, component A comprises 40-80 parts vinyl silicone resin, 30-60 parts vinyl silicone oil, 10-20 parts MQ silicone resin without active hydrogen groups, 1-5 parts vinyl POSS and 0.01-0.1 parts catalyst;

[0055] By weight, component B comprises 10-50 parts of hydrogen-containing silicone oil, 10-20 parts of MQ silicone resin, 0-5 parts of vinyl-free POSS, and 0.01-0.1 parts of inhibitor;

[0056] Of which, based on the total mass of silicone, the mass content of boron nitride is 0.1% to 1%.

[0057] In the silicone rubber of this application, boron nitride is distributed within the polymer network of the silicone rubber, which enhances the mechanical properties of the silicone rubber and enables it to withstand stronger external stresses. Simultaneously, boron nitride facilitates rapid heat dissipation within the silicone rubber, reducing combustion caused by localized overheating. Furthermore, in a combustion environment, boron nitride forms a dense insulating layer on the surface of the silicone rubber, thereby isolating it from external oxygen and further reducing the likelihood of subsequent combustion, thus improving the flame-retardant properties of the silicone rubber.

[0058] In this application, MQ silicone resin is a type of organosilicon resin with siloxane as the main chain, and its molecular structure is composed of M units (monofunctional siloxane units) and Q units (tetrafunctional siloxane units). POSS refers to polyhedral oligomeric silsesquioxane.

[0059] It is understood that, based on the total mass of silicone, the mass content of boron nitride includes, but is not limited to, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, or a range consisting of any two of these point values ​​as endpoints.

[0060] Furthermore, the mass content of boron nitride is 0.25% to 0.75%.

[0061] The aforementioned silicone rubber, by adding a small amount of boron nitride, can possess both excellent mechanical properties and flame retardant properties, while remaining safe and non-toxic.

[0062] Understandably, vinyl silicone resin, the largest component in component A, forms the "skeleton" of the colloid. As a three-dimensional network structure polysiloxane, it contains multiple reactive vinyl groups (Vi, CH2=CH-), significantly influencing the hardness, strength, modulus, heat resistance, and adhesion of silicone. Vinyl silicone oil, acting as an active diluent and toughening agent, can regulate the flowability, modulus, and elongation of silicone. MQ silicone resin, free of active hydrogen groups, acts as a reinforcing agent, improving the mechanical strength and adhesion of silicone. POSS, a polyhedral oligomeric silsesquioxane, is an organic-inorganic hybrid material with a nanoscale cage structure. Vinyl POSS has vinyl groups at each corner, allowing it to chemically bond to the vulcanized network, significantly improving the material's strength, hardness, heat resistance, and abrasion resistance even at extremely low dosages, while potentially enhancing optical transparency and flame retardancy.

[0063] Component B contains polysiloxane with active Si-H bonds. Under the action of a platinum catalyst, its Si-H bonds undergo a hydrosilylation reaction with the vinyl (Vi) in component A to form a Si-CH2-CH2-Si bridging structure, thereby achieving three-dimensional network cross-linking and curing from liquid to elastomer.

[0064] In some of these embodiments, the boron nitride is silane coupling agent modified boron nitride.

[0065] It is understood that this application uses a silane coupling agent to graft and modify boron nitride. The silane coupling agent can graft hydroxyl groups onto the surface of boron nitride, introduce organic functional groups, and change the surface of boron nitride from hydrophobic and inert to organic-friendly, making it less prone to agglomeration in the polymer matrix and forming a uniformly dispersed system; at the same time, it can also improve the solubility of boron nitride.

[0066] It is understood that the mass fractions of vinyl silicone resin in component A include, but are not limited to, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, and 80 parts, or any two of these point values ​​as end values ​​within a range.

[0067] It is understood that the mass fractions of vinyl silicone oil in component A include, but are not limited to, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, or any two of these point values ​​as end values ​​within a range.

[0068] It is understood that the mass fractions of MQ silicone resin in component A that do not contain active hydrogen groups include, but are not limited to, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20 parts, or any two of these point values ​​as end values ​​within a range.

[0069] It is understood that the mass fractions of vinyl POSS in component A include, but are not limited to, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, or any two of these point values ​​as end values ​​within a range.

[0070] It is understood that the mass fraction of catalyst in component A includes, but is not limited to, 0.01 parts, 0.02 parts, 0.03 parts, 0.04 parts, 0.05 parts, 0.06 parts, 0.07 parts, 0.08 parts, 0.09 parts, 0.1 parts, or any two of these point values ​​as end values ​​within a range.

[0071] In some of these embodiments, the boron nitride particle size is 1 μm to 2 μm.

[0072] It is understood that the particle size of boron nitride includes, but is not limited to, 1 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, and 2 μm, or any two of these values ​​as endpoints. Controlling the particle size of boron nitride within the above range can effectively improve its dispersion uniformity in organosilicone.

[0073] In some embodiments, the vinyl content in the vinyl silicone resin is 0.9% to 9% by mass. It is understood that the vinyl content in the vinyl silicone resin includes, but is not limited to, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, or a range consisting of any two of these point values ​​as endpoints.

[0074] In some embodiments, the vinyl content in the vinyl silicone oil is 0.1% to 0.5% by mass. It is understood that the vinyl content in the vinyl silicone oil includes, but is not limited to, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, or a range consisting of any two of these values ​​as endpoints.

[0075] In some embodiments, the viscosity of the vinyl silicone oil is 300 cps to 10000 cps. It is understood that the viscosity of the vinyl silicone oil includes, but is not limited to, 300 cps, 400 cps, 500 cps, 600 cps, 700 cps, 800 cps, 900 cps, 1000 cps, 1000 cps, 2000 cps, 3000 cps, 4000 cps, 5000 cps, 6000 cps, 7000 cps, 8000 cps, 9000 cps, 10000 cps, or any two of these point values ​​forming a range.

[0076] It should be noted that the viscosity of the vinyl silicone oil in this application refers to the viscosity obtained by testing at 100°C.

[0077] In some embodiments, the hydrogen content in the hydrogen-containing silicone oil is 0.1% to 0.5% by mass. It is understood that the hydrogen content in the hydrogen-containing silicone oil includes, but is not limited to, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, or a range consisting of any two of these values ​​as endpoints.

[0078] In some embodiments, component A contains a catalyst comprising a platinum complex. Further, component A contains a catalyst comprising a diluted platinum complex. Even further, the catalyst is diluted with a vinyl silicone oil with a viscosity of 100 cps. Even further, the dilution factor is 1000 times. Even further, the platinum complex is selected from platinum-divinylsiloxane complexes.

[0079] In some embodiments, the inhibitor in component B includes one or more of alkynyl alcohol inhibitors and silicone-based inhibitors. Further, the inhibitor is diluted with a vinyl silicone oil with a viscosity of 100 cps. Even further, the dilution factor is 1000 times.

[0080] In the aforementioned silicone rubber, the addition of boron nitride significantly reduced the heat release rate and total heat release, thus improving the flame retardant performance; at the same time, the release of CO and smoke particles was also controlled.

[0081] Some embodiments of this application also provide a method for preparing silicone rubber, comprising the following steps:

[0082] The raw materials are provided according to the aforementioned silicone materials;

[0083] Mix the raw materials for preparing component A to prepare component A;

[0084] Mix the raw materials for preparing component B to prepare component B;

[0085] Components A and B are mixed with boron nitride and cured to prepare silicone.

[0086] In some embodiments, before mixing components A and B with boron nitride, the following steps are included: sequentially crushing, ultrasonicating, and drying the boron nitride.

[0087] In some specific examples, the crushing process includes ball milling.

[0088] It is understandable that crushing and ultrasonic treatment of boron nitride can significantly improve its dispersibility and solubility; it is also more conducive to improving the flame retardant and mechanical properties of silicone.

[0089] In some embodiments, mixing component A, component B, and boron nitride includes the following steps:

[0090] Component A is mixed with boron nitride and dispersed to prepare a mixed slurry; then the mixed slurry is mixed with component B.

[0091] Understandably, dispersing and mixing component A with boron nitride first allows the curing reaction to proceed smoothly without affecting the function of boron nitride.

[0092] In some embodiments, the boron nitride is modified boron nitride, and the modifier of the modified boron nitride includes a silane coupling agent; the content of the silane coupling agent is 0.5% to 1.5% based on the total mass of the modifier.

[0093] In some specific examples, the modifier also includes a solvent.

[0094] In some specific examples, the solvent includes ethanol.

[0095] In some specific examples, the solvent contains ethanol and water. More specifically, the volume ratio of ethanol to water is 9:1. It is understood that the moisture in the solvent and the moisture in the air provide a favorable grafting environment for the silane coupling agent.

[0096] In some embodiments, the content of silane coupling agent is 0.5% to 1.5% based on the total mass of the modifier.

[0097] It is understood that, based on the total mass of the modifier, the content of the silane coupling agent includes, but is not limited to, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, or any two of these point values ​​as end values ​​within a range.

[0098] Furthermore, based on the total mass of the modifier, the content of the silane coupling agent is 0.8%~1.2%.

[0099] Furthermore, based on the total mass of the modifier, the content of the silane coupling agent is 1%.

[0100] In some embodiments, the curing temperature is 65°C to 75°C and the curing time is 3 to 5 hours.

[0101] It is understood that the curing temperature includes, but is not limited to, 65℃, 66℃, 67℃, 68℃, 69℃, 70℃, 71℃, 72℃, 73℃, 74℃, 75℃, or any two of these point values ​​as end values ​​within a range.

[0102] It is understood that the curing time includes, but is not limited to, 3h, 4h, 5h, or any two of these point values ​​as end values ​​within a range.

[0103] The above preparation methods mainly involve physical processes and rarely involve chemical synthesis steps. Therefore, the preparation process is relatively safe and has little environmental pollution.

[0104] The present application will be further described below with reference to specific embodiments and comparative examples, but these should not be construed as limiting the scope of protection of the present application. Unless otherwise specified, the raw materials involved in the following specific embodiments are all commercially available, the instruments used are all commercially available, and the processes involved are conventionally selected by those skilled in the art unless otherwise specified.

[0105] The raw materials used in the embodiments and comparative examples of this application are from the following sources:

[0106] The vinyl silicone resin was purchased from Hubei Longsheng Sihai New Material Co., Ltd., model number SH-5202.

[0107] The vinyl silicone oil was purchased from Hubei Longsheng Sihai New Material Co., Ltd., model number JP-01V-10000;

[0108] The MQ silicone resin, which does not contain active hydrogen groups, was purchased from Hubei Xinyuhong Biomedical Technology Co., Ltd., model number MQ0012;

[0109] The vinyl POSS was purchased from Anhui Aiyota Silicone Oil Co., Ltd., model number IOTA 9502;

[0110] The platinum-divinylsiloxane complex was purchased from Guangzhou Silicon Friends New Materials Technology Co., Ltd., model number PT-5000YC;

[0111] The hydrogen-containing silicone oil was purchased from Jiujiang Runhe Synthetic Materials Co., Ltd., model number RH202-20;

[0112] The MQ silicone resin was purchased from Jiujiang Runhe Synthetic Materials Co., Ltd., and the model number is RH-CMQ-60.

[0113] The vinyl-free POSS was purchased from Anhui Aiyota Silicone Oil Co., Ltd., model IOTA 9501;

[0114] The ethynylcyclohexanol inhibitor was purchased from Guangzhou Silicon Friends New Materials Technology Co., Ltd., model number YZJ-1;

[0115] Hexagonal boron nitride was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; model number B106033.

[0116] Example 1

[0117] (1) Provide 60 parts of vinyl silicone resin, 35 parts of vinyl silicone oil, 15 parts of MQ silicone resin without active hydrogen groups, 3 parts of vinyl POSS, and 0.5 parts of platinum-divinylsiloxane complex diluted with vinyl silicone oil with a viscosity of 100 cps (dilution ratio of 1000:1); mix the above substances evenly to prepare component A.

[0118] (2) Provide 10 parts of hydrogen-containing silicone oil, 15 parts of MQ silicone resin, 2 parts of vinyl-free POSS, and 0.3 parts of ethynylcyclohexanol inhibitor diluted with vinyl silicone oil with a viscosity of 100 cps (dilution ratio of 1000:1); mix the above substances evenly to prepare component B.

[0119] (3) Boron nitride pretreatment: Weigh 4g of hexagonal boron nitride after ball milling, add 30mL of ethanol, and use an ultrasonic cell disruptor at 600W for 1h. Then, dry it in a vacuum drying oven at 60℃ for 6h to obtain the pretreated boron nitride. Boron nitride was modified using silane coupling agent and ethanol. The content of KH570 silane coupling agent was 1% based on the total mass of the modifier. The particle size of the modified boron nitride was 1μm~2μm.

[0120] (4) Based on the total mass of component A, component B and boron nitride, add 0.25wt% modified boron nitride to component A, and at the same time add n-heptane solution to dilute component A (the mass ratio of n-heptane to component A is 1:1). Use a 600W ultrasonic cell disruptor for 20 minutes, and then stir at 90℃ for 4 hours; wait until there is no odor.

[0121] (5) Mix component A and component B at a mass ratio of 1:1 to remove bubbles, and bake at 70°C for 4 hours to cure, thus obtaining silicone.

[0122] Example 2

[0123] It is basically the same as Example 1, except that the amount of modified boron nitride added in step (4) is different; specifically, the amount of modified boron nitride added in Example 2 is 0.5wt%.

[0124] Example 3

[0125] It is basically the same as Example 1, except that the amount of modified boron nitride added in step (4) is different; specifically, the amount of modified boron nitride added in Example 3 is 0.75wt.

[0126] Example 4

[0127] It is basically the same as Example 1, except that the amount of modified boron nitride added in step (4) is different; specifically, the amount of modified boron nitride added in Example 4 is 1 wt%.

[0128] Example 5

[0129] It is basically the same as Example 1, except that in step (4), an equal mass of unmodified boron nitride is used instead of silane coupling agent to modify boron nitride.

[0130] Example 6

[0131] The results are basically the same as in Example 1, except that the particle size of the modified boron nitride is different; specifically, the particle size of the modified boron nitride in Example 6 is 5 μm.

[0132] Example 7

[0133] It is basically the same as Example 1, except that in step (4), an equal mass of hydroxylated hexagonal boron nitride is used instead of silane coupling agent to modify boron nitride.

[0134] Comparative Example 1

[0135] It is basically the same as Example 1, except that it does not include step (3), that is, directly mixing component A and component B in proportion, degassing and curing.

[0136] Figures 1 to 4 The thermogravimetric infrared spectroscopy (TGA) results are shown for the organosilicone samples prepared in Comparative Example 1 and Example 3; wherein Figure 1 A 3D diagram of the thermogravimetric-infrared spectroscopy test results for Comparative Example 1; Figure 2 A 3D image of the thermogravimetric-infrared spectroscopy test results of Example 3; Figure 3 The peak values ​​of Comparative Example 1 and Example 3 were compared using thermogravimetric infrared spectroscopy at 500°C. Figure 4 The peak intensity changes of Comparative Example 1 and Example 3 at different times.

[0137] As shown in the figure, the pure organosilicon resin and the sample with added 0.75 wt% boron nitride have the same characteristic absorption peaks, including Si-O-Si, Si-C, -CH3, and -CH2-CH2- groups. This indicates that the addition of boron nitride did not change the intrinsic thermal degradation pathway of the organosilicon resin. However, the addition of boron nitride significantly reduced the intensity of these characteristic peaks (especially those corresponding to carbon-containing volatile products), proving that boron nitride can effectively inhibit the generation and release of organic pyrolysis volatiles, thereby reducing the fuel supply for gas-phase combustion.

[0138] At the temperature corresponding to the maximum thermogravimetric rate, the overall absorption intensity of the infrared spectrum of the boron nitride-containing sample decreased significantly, which is consistent with the increase in char residue in thermogravimetric analysis and the decrease in heat release rate in cone calorimetry. These results indicate that boron nitride promotes the formation of a denser and more stable condensed phase during material decomposition. This is because the high thermal conductivity of boron nitride facilitates heat diffusion and reduces local overheating, while its layered structure helps to construct a continuous physical barrier. This nanoscale shielding barrier effectively limits the diffusion of volatiles, blocks oxygen penetration, and slows down the thermal degradation process of the polymer matrix. These synergistic effects reduce the release of combustible volatiles, thereby inhibiting flame propagation and sustained combustion, achieving a flame-retardant effect.

[0139] The viscosity of components A and B after mixing with boron nitride in Examples 1-4 and Comparative Example 1 was tested according to GB / T2794, and the results are shown in Table 1.

[0140] Table 1

[0141]

[0142] The thermal conductivity of the silicone rubbers prepared in Examples 1-4 and Comparative Example 1 was determined according to GB / T 10295-2008; the pull-out force and shear force of the silicone rubbers on the glass surface were determined according to GB / T 7124; and the elongation at break and tensile strength were determined according to GB / T 528. The test results are shown in Table 2.

[0143] Table 2

[0144]

[0145] The heat release rate, total heat release, CO release rate and total smoke release of the organosilicone prepared in the above embodiments and comparative examples were measured in accordance with GB / T 16172, and the results are shown in Table 3.

[0146] Table 3

[0147]

[0148] The above results demonstrate that adding a small amount of modified boron nitride can achieve good flame retardant properties in silicone rubber, while improving heat release and smoke generation, and maintaining excellent mechanical strength. Untreated boron nitride improves the flame retardant properties of the colloid, with higher addition amounts yielding better results. However, untreated boron nitride or boron nitride with larger particle sizes has poor compatibility with silicone rubber, and its mechanical properties cannot meet requirements. The functional groups on the surface of hydroxy boron nitride can improve its compatibility and enhance flame retardant properties to some extent, but its mechanical properties are not good. Silane coupling agent-modified boron nitride is more effective, and the addition amount can be adjusted to meet specific requirements. This application achieves improved flame retardant properties without affecting the mechanical properties of the colloid, making silicone rubber have a wider range of applications.

[0149] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0150] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A silicone gum characterized by, The A component, the B component, and boron nitride are included. The A component includes 40-80 parts of a vinyl silicone resin, 30-60 parts of a vinyl silicone oil, 10-20 parts of an MQ silicone resin not containing an active hydrogen group, 1-5 parts of a vinyl POSS, and 0.01-0.1 parts of a catalyst, by mass fraction. The B component includes 10-50 parts of a hydrogen-containing silicone oil, 10-20 parts of an MQ silicone resin, 0-5 parts of a POSS not containing a vinyl group, and 0.01-0.1 parts of an inhibitor, by mass fraction. The mass content of the boron nitride is 0.1%-1% based on the total mass of the silicone gum.

2. The silicone gel according to claim 1, characterized in that, The boron nitride is a silane coupling agent-modified boron nitride. The particle size of the boron nitride is 1-2 μm.

3. The silicone gel of claim 1, wherein The silicone gum satisfies at least one of the following characteristics:

4. The silicone gel according to any one of claims 1 to 3, characterized in that, (1) The mass content of the vinyl group in the vinyl silicone resin is 0.9%-1.9%; (2) The mass content of the vinyl group in the vinyl silicone oil is 0.1%-0.5%; (3) The viscosity of the vinyl silicone oil is 300-10,000 cps; (4) The mass content of hydrogen in the hydrogen-containing silicone oil is 0.1%-0.5%. The silicone gum satisfies at least one of the following characteristics:

5. The silicone gel according to any one of claims 1 to 3, wherein (1) The catalyst in the A component includes a platinum gold complex; (2) The inhibitor in the B component includes one or more of an alkyne alcohol-based inhibitor and a silicone-based inhibitor. The method includes the following steps:

6. A method for producing a silicone gum, characterized by, The silicone gum according to any one of claims 1-5 is provided as a raw material; The A component is prepared by mixing the respective raw materials of the A component; The B component is prepared by mixing the respective raw materials of the B component; The A component, the B component, and the boron nitride are mixed, and cured to prepare the silicone gum. Before the A component, the B component, and the boron nitride are mixed, the boron nitride is subjected to a crushing treatment, an ultrasonic treatment, and a drying treatment in sequence.

7. The method of preparing a silicone gum according to claim 6, wherein The A component, the B component, and the boron nitride are mixed by the following steps:

8. The method of preparing a silicone gum according to claim 6, wherein The A component and the boron nitride are mixed and subjected to a dispersion treatment to prepare a mixed slurry, and then the mixed slurry and the B component are mixed. The boron nitride is a modified boron nitride, and the modifier of the modified boron nitride includes a silane coupling agent; the content of the silane coupling agent is 0.5%-1.5% based on the total mass of the modifier.

9. The method of preparing a silicone gum according to claim 6, wherein The curing temperature is 65-75°C, and the curing time is 3-5 h.

10. The method for producing a silicone gum according to any one of claims 6 to 9, characterized in that, ​

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