Organic silicon bonding sealing material and preparation method thereof

Abstract

The invention relates to the technical field of bonding and sealing materials, and provides an organic silicon bonding and sealing material and a preparation method thereof. The flame-retardant silicone rubber comprises the following components in parts by weight: 100 parts of alpha, omega-dihydroxy polydimethylsiloxane, 100-150 parts of an inorganic flame retardant, 8-20 parts of simethicone, 26-60 parts of a nitrogen-phosphorus composite flame retardant, 0-2 parts of a platinum-containing flame retardant, 1.6-5 parts of a first organic silicon cross-linking agent, 1.6-5 parts of a second organic silicon cross-linking agent, 1.6-5 parts of a silane coupling agent and 1.6-5 parts of a catalyst. Wherein the inorganic flame retardant is selected from at least one of aluminum hydroxide and magnesium hydroxide. Through the arrangement, the organic silicon bonding sealing material disclosed by the invention not only has good flame retardant property, but also can keep good bonding property.

Description

Technical Field

[0001] The present application relates to the technical field of adhesive sealing materials, and particularly to an organosilicon adhesive sealing material and a preparation method thereof. Background Art

[0002] With the rapid development of the electronics and new energy fields, organosilicon adhesive sealants have become indispensable materials for ensuring the stable operation of various equipment due to their advantages such as good adhesiveness, weather resistance, chemical stability, and electrical insulation properties.

[0003] However, with the development of the industry, the market's safety requirements for electronic devices and the like are continuously increasing. Among them, the flame retardancy performance has become a key index that urgently needs to be improved for organosilicon adhesive sealants. The integration of electronic devices is getting higher and higher, the power density is continuously increasing, the heat generated by internal electronic components is increasing, and the risk of electrical faults is increasing. Once an electric spark is generated due to a short circuit, if the adhesive sealant is not flame retardant, it is extremely easy to be ignited, and the fire will spread rapidly, not only causing damage to the equipment, but also possibly resulting in data loss; in the new energy field, taking a new energy vehicle battery pack as an example, if the high-temperature open fire generated by battery thermal runaway cannot be effectively blocked by a flame retardant adhesive sealant, it will cause the vehicle to catch fire or even explode, seriously threatening personal and property safety; if a solar power station catches fire due to a non-flame-retardant adhesive sealing material, the damage of a large area of photovoltaic modules will cause huge economic losses.

[0004] Although existing ordinary organosilicon adhesive sealants have good adhesiveness and sealing properties, their flame retardancy is insufficient. The traditional improvement method is to add flame retardants. However, the addition of a large amount of flame retardants will damage the original flexibility, adhesive strength and other properties of organosilicon materials, reducing the sealing reliability. Therefore, there is an urgent need to develop an organosilicon adhesive sealing material that can not only have high flame retardancy performance, but also have good adhesive properties. Summary of the Invention

[0005] The purpose of the present application is to provide an organosilicon adhesive sealing material and a preparation method thereof to improve the flame retardancy performance of the organosilicon adhesive sealing material, and at the same time, it can also maintain good adhesive properties. The specific technical solutions are as follows:

[0006] The first aspect of the present application provides an organosilicon adhesive sealing material, which is prepared from the following components in parts by weight: 100 parts of α,ω-dihydroxypolydimethylsiloxane, 100 - 150 parts of inorganic flame retardant, 8 - 20 parts of dimethyl silicone oil, 26 - 60 parts of nitrogen-phosphorus compound flame retardant, 0 - 2 parts of platinum-containing flame retardant, 1.6 - 5 parts of the first organosilicon crosslinking agent, 1.6 - 5 parts of the second organosilicon crosslinking agent, 1.6 - 5 parts of silane coupling agent, 1.6 - 5 parts of catalyst; wherein, the inorganic flame retardant is selected from at least one of aluminum hydroxide and magnesium hydroxide.

[0007] In some embodiments of the present application, the viscosity of the α,ω-dihydroxypolydimethylsiloxane is 500 to 50000 mPa·s; preferably, the viscosity of the α,ω-dihydroxypolydimethylsiloxane is 20000 to 50000 mPa·s.

[0008] In some embodiments of the present application, the viscosity of the dimethyl silicone oil is 50 to 500 mPa·s; preferably, the viscosity of the dimethyl silicone oil is 50 to 100 mPa·s.

[0009] In some embodiments of the present application, the particle size D50 of the inorganic flame retardant is 2 to 20 μm; preferably, the particle size D50 of the inorganic flame retardant is 2 to 10 μm.

[0010] In some embodiments of the present application, the nitrogen-phosphorus compound flame retardant is selected from at least one of ammonium polyphosphate, melamine polyphosphate, and hexaphenoxycyclotriphosphazene.

[0011] In some embodiments of the present application, the first organosilicon crosslinking agent and the second organosilicon crosslinking agent are selected from one of methyltrimethoxysilane, methyltriethoxysilane, tetramethoxysilane, tetraethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane; the first organosilicon crosslinking agent and the second organosilicon crosslinking agent are selected from different substances.

[0012] In some embodiments of the present application, the silane coupling agent is selected from at least one of γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and γ-(methacryloyloxy)propyltrimethoxysilane.

[0013] In some embodiments of the present application, the catalyst is selected from at least one of tetra(isopropyl) titanate, tert-butyl titanate, titanate complex, dibutyltin diacetate, dibutyltin dilaurate, and organotin chelate.

[0014] The second aspect of the present application provides a preparation method of the organosilicon adhesive sealing material provided in the first aspect of the present application, which includes the following steps:

[0015] (1) Mix and dehydrate the α,ω-dihydroxypolydimethylsiloxane and the inorganic flame retardant, and obtain a masterbatch after grinding;

[0016] (2) After cooling the masterbatch obtained in the step (1), mix the masterbatch with dimethyl silicone oil, nitrogen-phosphorus compound flame retardant, first organosilicon crosslinking agent, second organosilicon crosslinking agent, silane coupling agent, and platinum-containing flame retardant, and perform the first stirring under vacuum conditions; then add the catalyst and perform the second stirring under vacuum conditions to obtain the organosilicon adhesive sealing material.

[0017] In some embodiments of the present application, in the step (1), the temperature for the mixed water removal is 120 - 150 °C, the stirring speed is 2000 - 3000 rpm, the vacuum degree is -0.1 MPa to -0.095 MPa, and the time is 2 - 3 h.

[0018] In some embodiments of the present application, in the step (2), the cooling temperature ≤ 40 °C; the vacuum degree for the first stirring is -0.1 MPa to -0.095 MPa, the stirring speed is 20 - 50 rpm, and the stirring time is 20 - 30 min; the vacuum degree for the second stirring is -0.1 MPa to -0.095 MPa, the stirring speed is 20 - 50 rpm, and the stirring time is 30 - 50 min.

[0019] Advantages of the present application:

[0020] The present application provides a silicone bonding and sealing material and a preparation method thereof. The silicone bonding and sealing material is prepared from the following components in parts by weight: 100 parts of α,ω-dihydroxypolydimethylsiloxane, 100 - 150 parts of inorganic flame retardant, 8 - 20 parts of dimethyl silicone oil, 26 - 60 parts of nitrogen-phosphorus compound flame retardant, 0 - 2 parts of platinum-containing flame retardant, 1.6 - 5 parts of the first silicone cross-linking agent, 1.6 - 5 parts of the second silicone cross-linking agent, 1.6 - 5 parts of silane coupling agent, and 1.6 - 5 parts of catalyst; wherein, the inorganic flame retardant is selected from at least one of aluminum hydroxide and magnesium hydroxide. Through the above settings, the silicone bonding and sealing material of the present application not only has good flame retardant performance, but also can maintain good bonding performance.

[0021] Of course, it is not necessary for any product or method of implementing the present application to simultaneously achieve all the above-mentioned advantages. Detailed embodiments

[0022] The technical solutions in the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those skilled in the art based on the present application belong to the scope of protection of the present application.

[0023] The first aspect of the present application provides a silicone bonding and sealing material, which is prepared from the following components in parts by weight: 100 parts of α,ω-dihydroxypolydimethylsiloxane, 100-150 parts of inorganic flame retardant, 8-20 parts of dimethyl silicone oil, 26-60 parts of nitrogen-phosphorus compound flame retardant, 0-2 parts of platinum-containing flame retardant, 1.6-5 parts of the first silicone crosslinking agent, 1.6-5 parts of the second silicone crosslinking agent, 1.6-5 parts of silane coupling agent, and 1.6-5 parts of catalyst; wherein, the inorganic flame retardant is selected from at least one of aluminum hydroxide and magnesium hydroxide.

[0024] It has been found that the silicone bonding and sealing material prepared according to the raw materials and ratios of the present application has both good flame retardant properties and good bonding properties. In the present application, the inorganic flame retardant is used as the main flame retardant. The inorganic flame retardant has the characteristics of low smoke generation, low toxicity, and low generation amount of harmful gases, and has a relatively high decomposition temperature and large heat absorption. It can effectively reduce the material temperature and the concentration of combustible gases, thereby achieving the flame retardant effect. At the same time, within the scope of the present application, the inorganic flame retardant is beneficial to reducing the curing shrinkage rate and reducing the interfacial stress, thereby improving the bonding performance of the silicone bonding and sealing material. Further, the silicone bonding and sealing material of the present application also includes a nitrogen-phosphorus compound flame retardant. On the one hand, during the combustion process, the nitrogen-phosphorus compound flame retardant can promote the formation of a dense carbon layer on the surface of the material, isolating the transfer of oxygen and heat and preventing the further spread of combustion; on the other hand, the nitrogen-phosphorus compound flame retardant will release non-combustible gases such as carbon dioxide and nitrogen during the combustion process, thereby diluting the concentration of combustible gases and oxygen and capturing free radicals to interrupt the combustion chain reaction, achieving a further flame retardant effect. In addition, the addition of the nitrogen-phosphorus compound flame retardant is beneficial to reducing the total amount of inorganic flame retardant required to reach the flame retardant grade, thereby improving the mechanical properties and processing properties of the silicone bonding and sealing material. The combination of the inorganic flame retardant and the nitrogen-phosphorus compound flame retardant is also beneficial to reducing the amount of the nitrogen-phosphorus compound flame retardant and reducing the production cost. The silicone bonding and sealing material of the present application includes α,ω-dihydroxypolydimethylsiloxane, inorganic flame retardant, dimethyl silicone oil, nitrogen-phosphorus compound flame retardant, the first silicone crosslinking agent, the second silicone crosslinking agent, silane coupling agent, and catalyst at the same time, and the weight parts of each component are adjusted within the scope of the present application. Each component acts synergistically, making the silicone bonding and sealing material have both good flame retardant properties and good bonding properties. Still further, the silicone bonding and sealing material of the present application may also include a platinum-containing flame retardant. Through catalytic action, the platinum-containing flame retardant causes the side chain organic groups of the silicone bonding and sealing material to undergo oxidative crosslinking reactions, increasing the crosslinking density, thereby improving the thermal stability of the silicone bonding and sealing material, preventing its further decomposition, and being beneficial to increasing the content of residues after combustion and promoting the formation of a ceramic layer, and then isolating the air to extinguish the flame.

[0025] This application uses α,ω-dihydroxypolydimethylsiloxane as the base rubber compound, and is combined with inorganic flame retardants, inorganic flame retardants, nitrogen-phosphorus compound flame retardants, platinum-containing flame retardants, the first organosilicon crosslinking agent, the second organosilicon crosslinking agent, silane coupling agents, and catalysts. By controlling the contents of each substance within the scope of this application, the components work synergistically to endow the organosilicon bonding and sealing material with both good flame retardancy and good bonding performance at the same time.

[0026] In some embodiments of this application, the bonding and sealing material is prepared from the following components in parts by weight:

[0027] 100 parts of α,ω-dihydroxypolydimethylsiloxane, 120 - 150 parts of inorganic flame retardant, 8 - 20 parts of dimethyl silicone oil, 26 - 40 parts of nitrogen-phosphorus compound flame retardant, 0 - 2 parts of platinum-containing flame retardant, 1.6 - 5 parts of the first organosilicon crosslinking agent, 1.6 - 5 parts of the second organosilicon crosslinking agent, 1.6 - 5 parts of silane coupling agent, 1.6 - 5 parts of catalyst. By controlling the contents of each substance within the scope of this application, the components work synergistically to endow the organosilicon bonding and sealing material with both good flame retardancy and good bonding performance at the same time.

[0028] In some embodiments of this application, the viscosity of α,ω-dihydroxypolydimethylsiloxane is 500 - 50000 mPa·s; preferably, the viscosity of α,ω-dihydroxypolydimethylsiloxane is 20000 - 50000 mPa·s. For example, the viscosity of α,ω-dihydroxypolydimethylsiloxane can be 500 mPa·s, 1000 mPa·s, 15000 mPa·s, 20000 mPa·s, 25000 mPa·s, 30000 mPa·s, 35000 mPa·s, 40000 mPa·s, 45000 mPa·s, 50000 mPa·s or any range composed of any two of these values. By controlling the viscosity of α,ω-dihydroxypolydimethylsiloxane within the scope of this application, it is beneficial to control the viscosity of the organosilicon bonding and sealing material within a suitable range, which is beneficial to enhancing the bonding performance of the organosilicon bonding and sealing material and adjusting the curing speed and curing performance.

[0029] In some embodiments of the present application, the viscosity of dimethyl silicone oil is 50 to 500 mPa·s; preferably, the viscosity of dimethyl silicone oil is 50 to 100 mPa·s. For example, the viscosity of dimethyl silicone oil can be 50 mPa·s, 80 mPa·s, 100 mPa·s, 150 mPa·s, 200 mPa·s, 250 mPa·s, 300 mPa·s, 350 mPa·s, 400 mPa·s, 450 mPa·s, 500 mPa·s or a range composed of any two of these values. By controlling the viscosity of dimethyl silicone oil within the scope of the present application, it is beneficial to control the viscosity of the silicone adhesive sealant within a suitable range, which is beneficial to enhancing the bonding performance of the silicone adhesive sealant and regulating the curing speed and curing performance.

[0030] In some embodiments of the present application, the particle size D50 of the inorganic flame retardant is 2 to 20 μm, preferably 2 to 10 μm. For example, the particle size D50 of the inorganic flame retardant can be 2 μm, 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, 18 μm, 20 μm or a range composed of any two of these values. By controlling the average particle size of the inorganic flame retardant within the scope of the present application and in combination with other components of the present application, it is beneficial to improve the flame retardant performance of the silicone adhesive sealant and maintain good bonding performance. When the particle size D50 of the inorganic flame retardant is too small, such as less than 2 μm, it will increase the viscosity of the silicone adhesive sealant and affect the subsequent processing performance; when the particle size D50 of the inorganic flame retardant is too large, such as greater than 20 μm, the viscosity of the silicone adhesive sealant will be too low, the mechanical strength will be reduced, and the tensile strength and shear strength will be reduced. Among them, D50 is the particle size corresponding to 50% of the cumulative volume when measured from the small particle size in the particle size distribution based on the volume of the inorganic flame retardant particles. In the present application, the inorganic flame retardant can be prepared or purchased, and the inorganic flame retardant with the required particle size can be selected in combination with the "Test of Inorganic Flame Retardant D50" provided in the present application.

[0031] In some embodiments of the present application, the nitrogen-phosphorus compound flame retardant is selected from at least one of ammonium polyphosphate (APP), melamine polyphosphate (MPP), and hexaphenoxycyclotriphosphazene. By selecting the nitrogen-phosphorus compound flame retardant within the scope of the present application, it is beneficial to exert the flame retardant effect of the nitrogen-phosphorus compound flame retardant. On the one hand, during the combustion process, the nitrogen-phosphorus compound flame retardant can promote the formation of a dense carbon layer on the material surface, isolate the transfer of oxygen and heat, and prevent the spread of combustion. On the other hand, the nitrogen-phosphorus compound flame retardant will release non-combustible gases during the combustion process, thereby diluting the concentration of combustible gases and oxygen, and capturing free radicals to interrupt the combustion chain reaction, achieving a further flame retardant effect. If the weight part of the nitrogen-phosphorus compound flame retardant in the raw material components of the silicone bonding and sealing material is too low, for example, less than 26 parts, it is not conducive to improving the flame retardant performance of the prepared inorganic silicone bonding and sealing material, and the flame retardant grade cannot reach the effect of V-0. If the weight part of the nitrogen-phosphorus compound flame retardant in the raw material components of the silicone bonding and sealing material is too high, for example, more than 60 parts, it is not conducive to improving the mechanical strength of the silicone bonding and sealing material, is not conducive to improving the bonding performance of the silicone bonding and sealing material, and will increase the cost of the silicone bonding and sealing material.

[0032] In some embodiments of the present application, the first silicone cross-linking agent and the second silicone cross-linking agent are selected from one of methyltrimethoxysilane, methyltriethoxysilane, tetramethoxysilane, tetraethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane; the first silicone cross-linking agent and the second silicone cross-linking agent are selected from different substances. By selecting two different silicone cross-linking agents in the present application, they act synergistically to cross-link and cure, and can simultaneously take into account the surface drying time and mechanical properties of the silicone bonding and sealing material.

[0033] In some embodiments of the present application, the silane coupling agent is selected from at least one of γ-aminopropyltriethoxysilane (KH-550), γ-(2,3-epoxypropoxy)propyltrimethoxysilane (KH-560), γ-mercaptopropyltrimethoxysilane (KH-590), and γ-(methacryloyloxy)propyltrimethoxysilane (KH-570). By selecting the silane coupling agent within the scope of the present application and using it in combination with the first silicone cross-linking agent and the second silicone cross-linking agent of the present application, it is beneficial for the silicone bonding and sealing material to achieve the bonding effect on different substrates while curing, and improve the bonding performance of the silicone bonding and sealing material.

[0034] In some embodiments of the present application, the catalyst is selected from at least one of tetraisopropyl titanate, tert-butyl titanate, titanate complex, dibutyltin diacetate, dibutyltin dilaurate, and organotin chelate. Among them, the titanate complex can be selected from at least one of titanium acetylacetonate, titanium ethylacetoacetate, and titanium lactate; the organotin chelate can be selected from at least one of dibutyltin acetylacetonate and dibutyltin dimercaptoacetate. By selecting the catalyst within the scope of the present application, it is beneficial to accelerate the curing speed of the silicone bonding and sealing material.

[0035] In the present application, the platinum-containing flame retardant is selected from at least one of platinum-divinyltetramethyldisiloxane complex (CAS No.: 68478-92-2), platinum-cyclohexenylmethylsiloxane complex (CAS No.: 68951-97-9), and isopropyl alcohol solution of chloroplatinic acid (CAS No.: 51849-78-2). By selecting the platinum-containing catalyst of the present application, the side-chain organic groups of the silicone bonding and sealing material undergo oxidative cross-linking reactions, increasing the cross-linking density, thereby improving the thermal stability of the silicone bonding and sealing material, preventing its further decomposition, and also facilitating an increase in the content of residues after combustion, promoting the formation of a ceramic layer, and then isolating air to extinguish the flame.

[0036] The present application places no particular limitation on the sources of α,ω-dihydroxypolydimethylsiloxane, inorganic flame retardant, dimethyl silicone oil, nitrogen-phosphorus compound flame retardant, platinum-containing flame retardant, first silicone cross-linking agent, second silicone cross-linking agent, silane coupling agent, and catalyst, which can be obtained by purchase or by preparation.

[0037] The second aspect of the present application provides a method for preparing the silicone bonding and sealing material provided in the first aspect of the present application, which includes the following steps:

[0038] (1) Mix α,ω-dihydroxypolydimethylsiloxane and an inorganic flame retardant and remove water, and obtain a masterbatch after grinding;

[0039] (2) After cooling the masterbatch obtained in step (1), mix the masterbatch with dimethyl silicone oil, nitrogen-phosphorus compound flame retardant, first silicone cross-linking agent, second silicone cross-linking agent, silane coupling agent, and platinum-containing flame retardant, and perform the first stirring under vacuum conditions; then add the catalyst and perform the second stirring under vacuum conditions to obtain the silicone bonding and sealing material.

[0040] The device for mixing and dehydrating in step (1) of the present application is not particularly limited as long as the object of the present application can be achieved. For example, a planetary stirring kettle can be used. The device for grinding in step (1) of the present application is not particularly limited as long as the object of the present application can be achieved. For example, a three-roll grinder can be used. The devices for the first stirring and the second stirring in step (2) of the present application are not particularly limited as long as the object of the present application can be achieved. For example, a planetary stirring kettle can be used.

[0041] In some embodiments of the present application, the temperature for mixing and dehydrating in step (1) is 120~150°C, the stirring speed is 2000~3000 rpm, the vacuum degree is -0.1 MPa to -0.095 MPa, and the time is 2~3 h. For example, the temperature for mixing and dehydrating can be 120°C, 130°C, 140°C, 150°C or a range composed of any two of these values; the stirring speed can be 2000 rpm, 2200 rpm, 2500 rpm, 2800 rpm, 3000 rpm or a range composed of any two of these values; the vacuum degree can be -0.1 MPa, -0.099 MPa, -0.098 MPa, -0.097 MPa, -0.096 MPa, -0.095 MPa or a range composed of any two of these values; the time can be 2 h, 2.2 h, 2.5 h, 2.8 h, 3 h or a range composed of any two of these values. Through the above steps, a masterbatch with good dispersion and dehydrated can be obtained. By controlling the temperature, stirring speed, vacuum degree and stirring time in step (1) within the above ranges, it is beneficial to remove the moisture in α,ω-dihydroxypolydimethylsiloxane and the inorganic flame retardant, and mix α,ω-dihydroxypolydimethylsiloxane and the inorganic flame retardant evenly to obtain the masterbatch.

[0042] In some embodiments of the present application, in step (2), the cooling temperature ≤ 40°C. For example, the cooling temperature can be 40°C, 38°C, 35°C, 32°C, 30°C, 28°C, 25°C or a range composed of any two of these values; the vacuum degree of the first stirring is from -0.1 MPa to -0.095 MPa, the stirring speed is 20 - 50 rpm, and the stirring time is 20 - 30 min. For example, the vacuum degree of the first stirring can be -0.1 MPa, -0.099 MPa, -0.098 MPa, -0.097 MPa, -0.096 MPa, -0.095 MPa or a range composed of any two of these values, the stirring speed can be 20 rpm, 25 rpm, 30 rpm, 35 rpm, 40 rpm, 45 rpm, 50 rpm or a range composed of any two of these values, and the stirring time can be 20 min, 22 min, 25 min, 28 min, 30 min or a range composed of any two of these values; the vacuum degree of the second stirring is from -0.1 MPa to -0.095 MPa, the stirring speed is 20 - 50 rpm, and the stirring time is 30 - 50 min. For example, the vacuum degree of the second stirring can be -0.1 MPa, -0.099 MPa, -0.098 MPa, -0.097 MPa, -0.096 MPa, -0.095 MPa or a range composed of any two of these values, the stirring speed can be 20 rpm, 25 rpm, 30 rpm, 35 rpm, 40 rpm, 45 rpm, 50 rpm or a range composed of any two of these values, and the stirring time can be 30 min, 35 min, 40 min, 45 min, 50 min or a range composed of any two of these values. By controlling the temperature, stirring speed, and vacuum degree in step (2) within the above ranges, it is beneficial to reduce the occurrence of side reactions and reduce the occurrence of local cross-linking reactions between the polymer and the cross-linking agent.

[0043] The preparation method provided by the present application has a simple process, is suitable for large-scale production, and the obtained organosilicon bonding and sealing material has good dispersibility and stability.

[0044] Examples

[0045] Hereinafter, examples and comparative examples are given to more specifically illustrate the embodiments of the present application. Various tests and evaluations are carried out according to the following methods. In addition, unless otherwise specified, "parts" and "%" are based on mass. All raw materials in the examples and comparative examples of the present application are commercially available.

[0046] Test methods and equipment:

[0047] Performance testing of organosilicon bonding and sealing materials

[0048] In accordance with the industry standard HG / T 5379-2018 "Organic Silicon Sealant for Electrical Appliances", the surface drying time, Shore hardness, tensile strength, elongation at break, shear strength, and flame retardant grade of the silicone bonding and sealing materials prepared in each example and comparative example of this application were tested.

[0049] Specific gravity refers to the ratio of the density of the substance (in a completely dense state) to the density of pure H2O at 3.98 °C under standard atmospheric pressure (999.972 kg / m 3 ). In this application, a hydrometer was used to test the specific gravity of the silicone bonding and sealing materials.

[0050] Shear strength can reflect the bonding performance of the silicone bonding and sealing materials. The greater the shear strength, the better the bonding performance of the silicone bonding and sealing materials.

[0051] Testing of Viscosity

[0052] The viscosity of the sample was tested using a Brookfield dial-type rotational viscometer. By this method, the viscosities of α,ω-dihydroxypolydimethylsiloxane, dimethyl silicone oil, and silicone bonding and sealing materials in this application can be tested.

[0053] Testing of the Particle Size D50 of Inorganic Flame Retardants

[0054] The particle size distribution of the inorganic flame retardant was tested using a laser particle size analyzer (instrument model: Malvern MS300) to obtain the particle size D50 of the inorganic flame retardant. Among them, the specific test was carried out in accordance with the national standard GB / T19077-2024 "Laser Diffraction Method for Particle Size Distribution". D50 represents the particle size corresponding to 50% cumulative volume when measured from the small particle size in the particle size distribution curve based on the volume of the material.

[0055] Example 1

[0056] Table 1

[0057] Table 1 shows the specific substances and weight parts of each component in Example 1. Among them, the viscosity of α,ω-dihydroxypolydimethylsiloxane is 20000 mPa·s, the viscosity of dimethyl silicone oil is 100 mPa·s, and the particle size D50 of aluminum hydroxide is 10 μm.

[0058] Preparation of Silicone Bonding and Sealing Materials:

[0059] (1) Add α,ω-dihydroxypolydimethylsiloxane and aluminum hydroxide into a planetary stirring kettle. Start the high-speed disperser, adjust the rotation speed to 2500 rpm, the temperature to 135 °C, and under a vacuum of -0.1 MPa, remove water under vacuum for 2.5 h. Then pass the mixture through a three-roll mill to obtain the masterbatch.

[0060] (2) Wait for the temperature of the masterbatch to drop to 30 °C, add dimethyl silicone oil, ammonium polyphosphate, methyltrimethoxysilane, vinyltrimethoxysilane, γ-aminopropyltriethoxysilane KH-550. Under a vacuum of -0.1 MPa, adjust the rotation speed to 35 rpm and stir for 25 min. Then add tetra-isopropyl titanate. Under a vacuum of -0.1 MPa, maintain the rotation speed at 35 rpm and stir for 35 min before discharging to obtain the silicone bonding and sealing material.

[0061] Example 2

[0062] Table 2

[0063] Table 2 shows the specific substances and weight parts of each component in Example 2. Except for adjusting the types and weight parts of each component of the silicone bonding and sealing material according to Table 2, the rest is the same as in Example 1.

[0064] Example 3

[0065] Table 3

[0066] Table 3 shows the specific substances and weight parts of each component in Example 3. Except for adjusting the types and weight parts of each component of the silicone bonding and sealing material according to Table 3, the rest is the same as in Example 1.

[0067] Example 4

[0068] Table 4

[0069] Table 4 shows the specific substances and weight parts of each component in Example 4. Except for adjusting the types and weight parts of each component of the silicone bonding and sealing material according to Table 4, the rest is the same as in Example 1.

[0070] Example 5

[0071] Table 5

[0072] Table 5 shows the specific substances and weight parts of each component in Example 5. Except for adjusting the types and weight parts of each component of the silicone bonding and sealing material according to Table 5, the rest is the same as in Example 1.

[0073] Example 6

[0074] Table 6

[0075] Table 6 shows the specific substances and parts by weight of each component in Example 6. Except for adjusting the types and parts by weight of each component of the silicone bonding and sealing material according to Table 6, the rest is the same as in Example 1.

[0076] Example 7

[0077] Table 7

[0078] Table 7 shows the specific substances and parts by weight of each component in Example 7. Except for adjusting the types and parts by weight of each component of the silicone bonding and sealing material according to Table 7, the rest is the same as in Example 1.

[0079] Example 8

[0080] Table 8

[0081] Table 8 shows the specific substances and parts by weight of each component in Example 8. Except for adjusting the types and parts by weight of each component of the silicone bonding and sealing material according to Table 8, the rest is the same as in Example 1. Among them, the platinum-containing flame retardant is a platinum-divinyltetramethyldisiloxane complex, and the CAS number is 68478-92-2.

[0082] Example 9

[0083] Except for adjusting the particle size D50 of aluminum hydroxide to 2 μm, the rest is the same as in Example 1.

[0084] Example 10

[0085] Except for adjusting the particle size D50 of aluminum hydroxide to 20 μm, the rest is the same as in Example 1.

[0086] Example 11

[0087] Except for adjusting the viscosity of α,ω-dihydroxypolydimethylsiloxane to 50000 mPa·s, the rest is the same as in Example 1.

[0088] Example 12

[0089] Except for adjusting the viscosity of α,ω-dihydroxypolydimethylsiloxane to 500 mPa·s, the rest is the same as in Example 1.

[0090] Example 13

[0091] Except that the viscosity of dimethyl silicone oil was adjusted to 50 mPa·s, the rest was the same as in Example 1.

[0092] Example 14

[0093] Except that the viscosity of dimethyl silicone oil was adjusted to 500 mPa·s, the rest was the same as in Example 1.

[0094] Comparative Example 1

[0095] Table 9

[0096] Table 9 shows the specific substances and weight fractions of each component of Comparative Example 1. Except that the types and weight fractions of each component of the silicone bonding and sealing material were adjusted according to Table 9, the rest was the same as in Example 1.

[0097] Comparative Example 2

[0098] Table 10

[0099] Table 10 shows the specific substances and weight fractions of each component of Comparative Example 2. Except that the types and weight fractions of each component of the silicone bonding and sealing material were adjusted according to Table 10, the rest was the same as in Example 1.

[0100] Comparative Example 3

[0101] Table 11

[0102] Table 11 shows the specific substances and weight fractions of each component of Comparative Example 3. Except that the types and weight fractions of each component of the silicone bonding and sealing material were adjusted according to Table 11, the rest was the same as in Example 1.

[0103] Comparative Example 4

[0104] Table 12

[0105] Table 12 shows the specific substances and weight fractions of each component of Comparative Example 4. Except that the types and weight fractions of each component of the silicone bonding and sealing material were adjusted according to Table 12 and the nitrogen-phosphorus compound flame retardant was not included, the rest was the same as in Example 1.

[0106] Comparative Example 5

[0107] Table 13

[0108] Table 13 shows the specific substances and parts by weight of each component in Comparative Example 5. Except for adjusting the types and parts by weight of each component of the silicone bonding and sealing material according to Table 13, the rest is the same as in Example 1.

[0109] Table 14 shows the test results of each example and comparative example.

[0110] Table 14

[0111] As can be seen from Examples 1 to 14 in Table 14, by controlling the parts by weight of each component within the scope of this application, the flame retardant grade of the obtained silicone bonding and sealing material can reach V-0, the shear strength is relatively high, and other properties all meet the requirements, indicating that the silicone bonding and sealing material in the examples of this application can balance the flame retardant performance and bonding performance. In Comparative Example 1, the inorganic flame retardant within the scope of this application was not used, and its flame retardant grade was V-2, indicating that the silicone bonding and sealing material in Comparative Example 1 has poor flame retardant performance; in Comparative Example 2, the parts by weight of the inorganic flame retardant were less than 100 parts, and its flame retardant grade was V-1, indicating that the silicone bonding and sealing material in Comparative Example 2 has poor flame retardant performance; in Comparative Example 3, the parts by weight of the inorganic flame retardant were higher than 150 parts, and the parts by weight of the nitrogen-phosphorus compound flame retardant were relatively less than 26 parts. Although the shear strength increased, the flame retardant grade was V-1, indicating that the silicone bonding and sealing material in Comparative Example 3 cannot balance the bonding performance and flame retardant performance; in Comparative Example 4, the nitrogen-phosphorus compound flame retardant was not included, and its flame retardant grade was V-1, indicating that the silicone bonding and sealing material in Comparative Example 4 has poor flame retardant performance; in Comparative Example 5, the parts by weight of the nitrogen-phosphorus compound flame retardant exceeded 60 parts, and its shear strength deteriorated, only being 1.4 MPa, indicating that the silicone bonding and sealing material in Comparative Example 5 has poor bonding performance.

[0112] The above are only the preferred embodiments of this application, and are not intended to limit this application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of this application shall be included within the scope of protection of this application.

Claims

1. An organosilicon adhesive and sealant material, which is prepared from the following components in parts by weight: 100 parts of α,ω-dihydroxypolydimethylsiloxane, 100 - 150 parts of inorganic flame retardant, 8 - 20 parts of dimethyl silicone oil, 26 - 60 parts of nitrogen-phosphorus compound flame retardant, 0 - 2 parts of platinum-containing flame retardant, 1.6 - 5 parts of the first organosilicon crosslinking agent, 1.6 - 5 parts of the second organosilicon crosslinking agent, 1.6 - 5 parts of silane coupling agent, 1.6 - 5 parts of catalyst; Among them, The inorganic flame retardant is selected from at least one of aluminum hydroxide and magnesium hydroxide.

2. The silicone bonding and sealing material according to claim 1, wherein, The viscosity of the α,ω-dihydroxypolydimethylsiloxane is 500 - 50000 mPa·s.

3. The silicone bonding and sealing material according to claim 1, wherein, The viscosity of the α,ω-dihydroxypolydimethylsiloxane is 20000 - 50000 mPa·s.

4. The silicone bonding and sealing material according to claim 1, wherein, The viscosity of the dimethyl silicone oil is 50 - 500 mPa·s.

5. The silicone bonding and sealing material according to claim 1, wherein, The viscosity of the dimethyl silicone oil is 50 - 100 mPa·s.

6. The silicone bonding and sealing material according to claim 1, wherein The particle size D50 of the inorganic flame retardant is 2 - 20 μm.

7. The silicone bonding and sealing material according to claim 1, wherein, The particle size D50 of the inorganic flame retardant is 2 - 10 μm.

8. The silicone bonding and sealing material according to claim 1, wherein, The nitrogen-phosphorus compound flame retardant is selected from at least one of ammonium polyphosphate, melamine polyphosphate and hexaphenoxycyclotriphosphazene.

9. The silicone bonding and sealing material according to claim 1, wherein The first organosilicon crosslinking agent and the second organosilicon crosslinking agent are selected from one of methyltrimethoxysilane, methyltriethoxysilane, tetramethoxysilane, tetraethoxysilane, vinyltrimethoxysilane and vinyltriethoxysilane; the first organosilicon crosslinking agent and the second organosilicon crosslinking agent are selected from different substances.

10. The silicone bonding and sealing material according to claim 1, wherein, The silane coupling agent is selected from at least one of γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane and γ-(methacryloyloxy)propyltrimethoxysilane; and / or, the catalyst is selected from at least one of tetra(isopropyl) titanate, tert-butyl titanate, titanate complex, dibutyltin diacetate, dibutyltin dilaurate and organotin chelate.

11. A preparation method of the organosilicon adhesive and sealant material according to any one of claims 1 to 10, which comprises the following steps: (1) Mix and dehydrate α,ω-dihydroxypolydimethylsiloxane and inorganic flame retardant, and obtain the masterbatch after grinding; (2) After cooling the masterbatch obtained in step (1), mix the masterbatch with dimethyl silicone oil, nitrogen-phosphorus compound flame retardant, the first organosilicon crosslinking agent, the second organosilicon crosslinking agent, silane coupling agent, platinum-containing flame retardant, and perform the first stirring under vacuum conditions; then add the catalyst and perform the second stirring under vacuum conditions to obtain the organosilicon adhesive and sealant material.

12. The preparation method of the silicone bonding and sealing material according to claim 11, wherein, In step (1), the temperature of the mixing and dehydration is 120 - 150 °C, the stirring speed is 2000 - 3000 rpm, the vacuum degree is -0.1 MPa to -0.095 MPa, and the time is 2 - 3 h.

13. The preparation method of the silicone bonding and sealing material according to claim 11, wherein, In the step (2), the cooling temperature ≤ 40°C; the vacuum degree of the first stirring is -0.1 MPa to -0.095 MPa, the stirring speed is 20 - 50 rpm, and the stirring time is 20 - 30 min; the vacuum degree of the second stirring is -0.1 MPa to -0.095 MPa, the stirring speed is 20 - 50 rpm, and the stirring time is 30 - 50 min.

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