A silicone foam adhesive and a method for preparing the same
By using graphene-modified acrylic resin and melamine-formaldehyde resin flame-retardant microcapsules, the problem of insufficient flame-retardant performance of silicone foam was solved, achieving high-efficiency flame retardancy and stable high and low temperature resistance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHENZHEN INST OF ADVANCED TECH CHINESE ACAD OF SCI
- Filing Date
- 2026-01-22
- Publication Date
- 2026-06-05
AI Technical Summary
Existing silicone foams have poor flame retardant properties. Traditional methods often involve high amounts of flame retardant filler, which leads to decreased mechanical properties or easy leakage of the flame retardant, and also results in insufficient temperature resistance.
Flame-retardant microcapsules, using graphene as the core material and modified acrylic resin and melamine-formaldehyde resin as the shell material, form an expanded char layer by generating inert gas through the layered physical barrier effect and high-temperature decomposition, thus achieving high-efficiency flame retardancy. At the same time, the use of a small number of microcapsules improves the limiting oxygen index and flame retardancy rating.
It significantly improves the limiting oxygen index of the foam to over 32% at low filler levels, achieving UL94V-0 rating, and maintains stable performance within the range of -60℃ to 200℃, with a compression set of ≤15%.
Smart Images
Figure CN122146050A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of adhesive technology, and in particular to an organosilicon foam and its preparation method. Background Technology
[0002] Silicone foam has excellent resistance to high and low temperatures, aging, and insulation properties, and is widely used in electronic packaging, building sealing, aerospace, and other fields. However, traditional silicone foam has poor flame retardant properties, with a limiting oxygen index (LOI) usually below 25%, making it difficult to meet the requirements of high flame retardant applications (such as fire protection for electronic equipment and sealing for rail transportation).
[0003] There are two main methods to improve the flame retardant properties of expanded polystyrene foam: one is to add inorganic flame retardants such as aluminum hydroxide and magnesium hydroxide. However, the high amount of flame retardant can easily lead to a decrease in the mechanical properties and expansion ratio of the expanded polystyrene foam. For example, patent CN120795626A discloses an open-cell silicone foam for battery packs and its preparation method, which uses aluminum hydroxide as a flame retardant material. The other method is to add single-shell flame retardant microcapsules (such as melamine-formaldehyde coated flame retardants). However, the single-shell structure is prone to rupture during the foaming process, leading to flame retardant leakage. In addition, the temperature resistance is insufficient, and it is easy to decompose and fail at high temperatures.
[0004] Based on the above analysis, it is essential to provide a foaming adhesive formulation with low filler content, high flame retardancy efficiency, and adaptability to the silicone foaming process. Summary of the Invention
[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an organosilicon foam and its preparation method, so as to solve the problems of high flame retardant filling amount and easy leakage of flame retardant in the prior art, while ensuring that the foam has excellent mechanical properties, high and low temperature resistance and stable flame retardant effect.
[0006] In a first aspect, the present invention provides an organosilicon foam, comprising component A and component B. Component A comprises the following raw materials: vinyl silicone oil, hydroxyl silicone oil, fumed silica, and platinum catalyst; component B comprises the following raw materials: vinyl silicone oil, hydrogen-containing silicone oil, fumed silica, flame-retardant microcapsules, and inhibitor; wherein the core material of the flame-retardant microcapsules is graphene, and the inner and outer shell materials are, in order, modified acrylic resin and melamine-formaldehyde resin. Graphene, as the core material, delays heat diffusion through the layered physical barrier effect; the modified acrylic resin, with the inner shell material obtained by reacting methyl methacrylate, ethyl acrylate, and KH570 coupling agent, forms a dense carbon layer after carbonization, achieving condensed phase flame retardancy; the outer shell material, melamine-formaldehyde resin, decomposes at high temperature to produce inert gases such as NH3, diluting the concentration of combustible gases, and simultaneously forming an expanded carbon layer to isolate oxygen and heat.
[0007] In some embodiments, the modified acrylic resin is obtained by reacting methyl methacrylate, ethyl acrylate, and KH570 coupling agent.
[0008] In some embodiments, the vinyl silicone oil has a vinyl content of 0.1%-0.5% and a viscosity of 500-5000 mPa. s; The hydrogen-containing silicone oil has a hydrogen content of 0.5%-1.5% and a viscosity of 100-1000 mPa. s.
[0009] In some embodiments, the fumed silica is hydrophobic and has a specific surface area of 150-300 m². 2 / g, with a particle size of 6-20nm.
[0010] In some embodiments, the platinum catalyst is a chloroplatinic acid-vinylsiloxane complex with a platinum content of 1000-5000 ppm.
[0011] In some embodiments, the inhibitor is at least one of ethynylcyclohexanol and tetramethyltetravinylcyclotetrasiloxane.
[0012] In some embodiments, the mass fractions of each raw material in component A are: 60-80 parts vinyl silicone oil, 5-15 parts hydroxyl silicone oil, 3-8 parts fumed silica, and 0.01-0.05 parts platinum catalyst.
[0013] In some embodiments, the mass fractions of each raw material in component B are: 50-70 parts vinyl silicone oil, 10-20 parts hydrogen-containing silicone oil, 3-8 parts fumed silica, 5-15 parts flame-retardant microcapsules, and 0.05-0.2 parts inhibitor.
[0014] Secondly, the present invention also provides a method for preparing the above-mentioned silicone foam, comprising the following steps: Preparation of component A: Vinyl silicone oil, hydroxyl silicone oil, fumed silica, and platinum catalyst were mixed evenly to obtain component A; Preparation of Component B: Vinyl silicone oil, hydrogen-containing silicone oil, fumed silica, flame-retardant microcapsules, and inhibitor are mixed evenly to obtain Component B; Foaming and curing: Mix components A and B evenly, heat to 60-80℃ to foam and cure, and you will get silicone foam.
[0015] In some embodiments, the flame-retardant microcapsules are prepared by the following process: S101, by weight, 1-3 parts graphene and 5-10 parts polyvinylpyrrolidone are mixed, 50-70 parts deionized water is added, and the mixture is ultrasonically dispersed to obtain a graphene dispersion. S102, by weight, 50-80 parts of methyl methacrylate, 30-40 parts of ethyl acrylate and 40-50 parts of anhydrous ethanol are mixed, 1-2 parts of KH570 coupling agent are added, and 0.5-1 parts of benzoyl peroxide are added under nitrogen protection. The mixture is heated to 80-85℃ to obtain a modified acrylic resin prepolymer. S103, by weight, add 0.5-1 part triethanolamine to 20-25 parts formaldehyde solution, adjust the pH to 8.0-9.0, stir, heat to 40-50℃, add 10-12 parts melamine, stir to dissolve, heat to 80-90℃ and keep the reaction at that temperature. After the reaction is complete, cool to room temperature, add dilute hydrochloric acid to adjust the pH to 6.5-7.0, and obtain melamine-formaldehyde prepolymer; S104, by weight, add 50-60 parts of modified acrylic resin prepolymer to 20-30 parts of graphene dispersion, add 0.5-1.5 parts of sodium dodecylbenzenesulfonate for emulsification and dispersion, and heat at 70-80℃ for 3-4 hours to obtain primary microspheres; S105, by weight, add 30-40 parts of melamine-formaldehyde prepolymer to 60-70 parts of primary microspheres, add 0.3-0.8 parts of styrene-maleic anhydride copolymer, add ammonia water to adjust the pH to 8.0-8.5, then solidify, centrifuge, and dry at 50-70℃ to obtain flame-retardant microcapsules.
[0016] The beneficial effects of the technical solution provided by this invention include: This invention uses flame-retardant microcapsules with an outer shell of melamine-formaldehyde resin, an inner shell of modified acrylic resin, and a core of graphene. Melamine-formaldehyde resin decomposes at high temperatures to produce inert gases (such as NH3), diluting the concentration of combustible gases; simultaneously, it forms an expanded char layer, isolating oxygen and heat. The modified acrylic resin carbonizes to form a dense char layer (condensed phase flame retardancy). Graphene delays heat diffusion through its layered physical barrier effect. Through the dual synergistic effect of the shell and core materials, adding only a small amount of flame-retardant microcapsules can increase the limiting oxygen index (LOI) of the foam to over 32%, achieving a vertical burning rating of UL94V-0, with no dripping. The foam maintains stable performance within the range of -60℃ to 200℃, and after high and low temperature cycling (-40℃ / 2h → 150℃ / 2h, 10 cycles), the compression set is ≤15%. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the process for preparing the silicone foam of the present invention. Detailed Implementation
[0018] To provide a clearer understanding of the technical features, objectives, and beneficial effects of this invention, the technical solution of this invention is described in detail below. This invention is not limited to the specific embodiments listed below. Those skilled in the art can implement this invention using various other specific embodiments based on the content disclosed herein. Any modifications or variations made to the design structure and concept of this invention fall within the protection scope of this invention. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.
[0019] Unless otherwise specified, the experimental methods in the following examples are conventional methods, and the experimental materials used are all commercially available products.
[0020] This invention provides an organosilicon foam that solves the problems of high flame retardant content and easy leakage of flame retardants in existing foams.
[0021] The following is a process flow of the preparation method of an organosilicon foam according to the present invention: Figure 1 As shown, the method for preparing silicone foam includes the following steps: Preparation of component A: Vinyl silicone oil, hydroxyl silicone oil, fumed silica, and platinum catalyst were mixed evenly to obtain component A; Preparation of Component B: Vinyl silicone oil, hydrogen-containing silicone oil, fumed silica, flame-retardant microcapsules, and inhibitor are mixed evenly to obtain Component B; Foaming and curing: Mix components A and B evenly, heat to 60-80℃ to foam and cure for 1-2 hours to obtain silicone foam.
[0022] Example 1: Preparation of flame-retardant microcapsules: (1) By mass, 1 part graphene and 6 parts polyvinylpyrrolidone were mixed, 60 parts deionized water were added, and the mixture was ultrasonically dispersed to obtain a graphene dispersion. (2) By mass, 55 parts of methyl methacrylate, 35 parts of ethyl acrylate and 50 parts of anhydrous ethanol were mixed, 1.5 parts of KH570 coupling agent were added, and 0.6 parts of benzoyl peroxide were added under nitrogen protection. The mixture was heated to 82°C to obtain a modified acrylic resin prepolymer. (3) Add 0.6 parts of triethanolamine to 20 parts of formaldehyde solution by mass, adjust the pH value to 8.0, stir, heat to 40°C, add 10 parts of melamine and stir to dissolve, heat to 85°C and keep warm for reaction, after the reaction is completed, cool to room temperature, add dilute hydrochloric acid to adjust the pH value to 7.0, and obtain melamine formaldehyde prepolymer; (4) Add 55 parts of modified acrylic resin prepolymer to 20 parts of graphene dispersion by mass, add 1 part of sodium dodecylbenzenesulfonate for emulsification and dispersion, and heat at 75°C for 3 hours to obtain primary microspheres. (5) By mass, 35 parts of melamine-formaldehyde prepolymer and 0.4 parts of styrene-maleic anhydride copolymer were added to 60 parts of primary microspheres. After adjusting the pH to 8.0 with ammonia, the mixture was cured, centrifuged, and dried at 60°C to obtain flame-retardant microcapsules.
[0023] Preparation of silicone foam: By weight, 65 parts of silicone foam with a vinyl content of 0.2% and a viscosity of 900 mPa are added. Component A is obtained by mixing 10 parts of vinyl silicone oil, 10 parts of hydroxyl silicone oil, 5 parts of hydrophobic fumed silica with a particle size of 20 nm and a specific surface area of 150 m² / g, and 0.02 parts of a chloroplatinic acid-vinylsiloxane complex with a platinum content of 2000 ppm. The mixture is stirred at 1200 rpm for 40 min. Component A is then obtained by mixing 60 parts of a vinyl silicone oil with a content of 0.4% and a viscosity of 750 mPa. s vinyl silicone oil, 15 parts, hydrogen content 0.8%, viscosity 600 mPa s-containing hydrogen silicone oil, 5 parts with a specific surface area of 150m² 2 / g, hydrophobic fumed silica with a particle size of 20nm, 8 parts flame retardant microcapsules, and 0.1 parts ethynylcyclohexanol are mixed evenly and stirred at 1000rpm for 35min to obtain component B; component A and component B are mixed evenly at a mass ratio of 1:1 and stirred at 500rpm for 6min, heated to 65℃ for foaming and curing for 1h to obtain silicone foam.
[0024] Example 2: Preparation of flame-retardant microcapsules: (1) By mass, 2.5 parts of graphene and 8 parts of polyvinylpyrrolidone were mixed, 60 parts of deionized water were added, and the mixture was ultrasonically dispersed to obtain a graphene dispersion. (2) By mass, 60 parts of methyl methacrylate, 40 parts of ethyl acrylate and 50 parts of anhydrous ethanol are mixed, 1.5 parts of KH570 coupling agent are added, and 0.6 parts of benzoyl peroxide are added under nitrogen protection. The mixture is heated to 85°C to obtain a modified acrylic resin prepolymer. (3) Add 1 part triethanolamine to 25 parts formaldehyde solution by mass, adjust the pH value to 9.0, stir, heat to 45°C, add 12 parts melamine and stir to dissolve, heat to 80°C and keep warm for reaction, after the reaction is completed, cool to room temperature, add dilute hydrochloric acid to adjust the pH value to 7.0, and obtain melamine formaldehyde prepolymer; (4) By mass, 60 parts of modified acrylic resin prepolymer were added dropwise to 25 parts of graphene dispersion, and 0.8 parts of sodium dodecylbenzenesulfonate were added for emulsification and dispersion. The mixture was heated at 80°C for 4 hours to obtain primary microspheres. (5) By mass, 30 parts of melamine-formaldehyde prepolymer and 0.4 parts of styrene-maleic anhydride copolymer were added to 65 parts of primary microspheres. After adjusting the pH to 8.5 with ammonia, the mixture was cured, centrifuged, and dried at 60°C to obtain flame-retardant microcapsules.
[0025] Preparation of silicone foam: By weight, 80 parts of silicone foam with a vinyl content of 0.3% and a viscosity of 850 mPa are added. 12 parts of vinyl silicone oil, 4 parts of fumed silica with a particle size of 15 nm and a specific surface area of 200 m² / g, and 0.03 parts of a chloroplatinic acid-vinylsiloxane complex with a platinum content of 5000 ppm were mixed evenly and stirred at 1500 rpm for 60 min to obtain component A; by mass, 70 parts of a vinyl content of 0.2% and a viscosity of 900 mPa were added. Vinyl silicone oil of type s, 10 parts, hydrogen content 0.7%, viscosity 900 mPa 6 parts of hydrogen-containing silicone oil, 6 parts of hydrophobic fumed silica with a specific surface area of 200 m² / g and a particle size of 15 nm, 10 parts of flame-retardant microcapsules, and 0.2 parts of inhibitor were mixed evenly and stirred at 1000 rpm for 40 min to obtain component B. Component A and component B were mixed evenly at a mass ratio of 1:1 and stirred at 600 rpm for 10 min. The mixture was then heated to 75℃ to foam and cured for 2 h to obtain silicone foam.
[0026] Example 3: Preparation of flame-retardant microcapsules: (1) By mass, 3 parts of graphene and 7 parts of polyvinylpyrrolidone were mixed, 65 parts of deionized water were added, and the mixture was ultrasonically dispersed to obtain a graphene dispersion. (2) By mass, 40 parts of methyl methacrylate, 32 parts of ethyl acrylate and 45 parts of anhydrous ethanol are mixed, 1 part of KH570 coupling agent is added, 1 part of benzoyl peroxide is added under nitrogen protection, and the mixture is heated to 85°C to obtain a modified acrylic resin prepolymer. (3) Add 0.6 parts of triethanolamine to 20 parts of formaldehyde solution by mass, adjust the pH value to 8.0, stir, heat to 40°C, add 10 parts of melamine, stir to dissolve, heat to 80°C and keep the reaction at that temperature. After the reaction is completed, cool to room temperature, add dilute hydrochloric acid to adjust the pH value to 6.5, and obtain melamine formaldehyde prepolymer. (4) Add 50 parts of modified acrylic resin prepolymer to 20 parts of graphene dispersion by mass, add 0.5 parts of sodium dodecylbenzenesulfonate for emulsification and dispersion, and heat at 80°C for 3 hours to obtain primary microspheres. (5) Add 40 parts of melamine-formaldehyde prepolymer and 0.6 parts of styrene-maleic anhydride copolymer to 70 parts of primary microspheres by mass. After adjusting the pH to 8.0 with ammonia, solidify, centrifuge, and dry at 65°C to obtain flame-retardant microcapsules.
[0027] Preparation of silicone foam: By weight, 80 parts of silicone foam with a vinyl content of 0.4% and a viscosity of 750 mPa are used. Component A is obtained by mixing 10 parts of vinyl silicone oil, 10 parts of hydroxyl silicone oil, 5 parts of hydrophobic fumed silica with a particle size of 10 nm and a specific surface area of 220 m² / g, and 0.05 parts of a chloroplatinic acid-vinylsiloxane complex with a platinum content of 4000 ppm. The mixture is stirred at 1500 rpm for 60 min. Component A is then obtained by mixing 50 parts by weight of a vinyl content of 0.5% and a viscosity of 600 mPa. s vinyl silicone oil, 15 parts, hydrogen content 1.0%, viscosity 550 mPa 5 parts of hydrogen-containing silicone oil, 5 parts of hydrophobic fumed silica with a specific surface area of 220 m² / g and a particle size of 10 nm, 12 parts of flame-retardant microcapsules, and 0.15 parts of ethynylcyclohexanol were mixed evenly and stirred at 1000 rpm for 50 min to obtain component B. Component A and component B were mixed evenly at a mass ratio of 1:1 and stirred at 800 rpm for 6 min. The mixture was then heated to 80℃ to foam and cured for 1.5 h to obtain silicone foam.
[0028] Example 4: Preparation of flame-retardant microcapsules: (1) By mass, 2.5 parts of graphene and 8 parts of polyvinylpyrrolidone were mixed, and 50 parts of deionized water were added. The mixture was then ultrasonically dispersed to obtain a graphene dispersion. (2) By mass, 60 parts of methyl methacrylate, 35 parts of ethyl acrylate and 40 parts of anhydrous ethanol are mixed, 1 part of KH570 coupling agent is added, 0.5 parts of benzoyl peroxide is added under nitrogen protection, and the mixture is heated to 85°C to obtain a modified acrylic resin prepolymer. (3) Add 0.6 parts of triethanolamine to 25 parts of formaldehyde solution by mass, adjust the pH value to 8.0, stir, heat to 40°C, add 10 parts of melamine, stir to dissolve, heat to 90°C and keep warm for reaction. After the reaction is completed, cool to room temperature, add dilute hydrochloric acid to adjust the pH value to 6.5, and obtain melamine formaldehyde prepolymer; (4) By mass, add 50 parts of modified acrylic resin prepolymer to 30 parts of graphene dispersion, and add 0.5 parts of styrene-maleic anhydride copolymer for emulsification and dispersion to obtain primary microspheres; (5) By mass, 30 parts of melamine-formaldehyde prepolymer and 0.5 parts of styrene-maleic anhydride copolymer were added to 65 parts of primary microspheres. After adjusting the pH to 8.0 with ammonia, the mixture was cured, centrifuged, and dried at 70°C to obtain flame-retardant microcapsules.
[0029] Preparation of silicone foam: By weight, 80 parts of silicone foam with a vinyl content of 0.5% and a viscosity of 600 mPa are added. 12 parts of vinyl silicone oil, 6 parts of hydrophobic fumed silica with a particle size of 9 nm and a specific surface area of 250 m² / g, and 0.05 parts of chloroplatinic acid-vinylsiloxane complex with a platinum content of 3000 ppm were mixed evenly and stirred at 1200 rpm for 40 min to obtain component A; by mass, 55 parts of vinyl content of 0.3% and viscosity of 850 mPa were added. s vinyl silicone oil, 15 parts, hydrogen content 1.2%, viscosity 400 mPa 6 parts of hydrogen-containing silicone oil, 6 parts of hydrophobic fumed silica with a specific surface area of 250 m² / g and a particle size of 9 nm, 10 parts of flame-retardant microcapsules, and 0.1 parts of tetramethyltetravinylcyclotetrasiloxane were mixed evenly and stirred at 1400 rpm for 35 min to obtain component B. Component A and component B were mixed evenly at a mass ratio of 1:1 and stirred at 600 rpm for 8 min. The mixture was then heated to 70℃ to foam and cured for 2 h to obtain silicone foam.
[0030] Example 5: Preparation of flame-retardant microcapsules: (1) By mass, 2.5 parts of graphene and 7 parts of polyvinylpyrrolidone were mixed, 60 parts of deionized water were added, and the mixture was ultrasonically dispersed to obtain a graphene dispersion. (2) By mass, 75 parts of methyl methacrylate, 35 parts of ethyl acrylate and 45 parts of anhydrous ethanol were mixed, 2 parts of KH570 coupling agent were added, and 0.8 parts of benzoyl peroxide were added under nitrogen protection. The mixture was heated to 85°C to obtain a modified acrylic resin prepolymer. (3) Add 0.6 parts of triethanolamine to 25 parts of formaldehyde solution by mass, adjust the pH value to 9.0, stir, heat to 50°C, add 12 parts of melamine and stir to dissolve, heat to 80°C and keep warm for reaction, after the reaction is completed, cool to room temperature, add dilute hydrochloric acid to adjust the pH value to 7.0, and obtain melamine formaldehyde prepolymer; (4) By mass, 60 parts of modified acrylic resin prepolymer were added dropwise to 20 parts of graphene dispersion, and 1.0 part of sodium dodecylbenzenesulfonate was added for emulsification and dispersion. The mixture was heated at 70°C for 3 hours to obtain primary microspheres. (5) By mass, 40 parts of melamine-formaldehyde prepolymer and 0.6 parts of styrene-maleic anhydride copolymer were added to 65 parts of primary microspheres. After adjusting the pH to 8.0 with ammonia, the mixture was cured, centrifuged and dried to obtain flame-retardant microcapsules.
[0031] Preparation of silicone foam: 72 parts by weight of silicone foam with a vinyl content of 0.3% and a viscosity of 850 mPa. Component A was obtained by mixing 15 parts of vinyl silicone oil, 15 parts of hydroxyl silicone oil, 6.5 parts of hydrophobic fumed silica with a particle size of 16 nm and a specific surface area of 180 m² / g, and 0.03 parts of a chloroplatinic acid-vinylsiloxane complex with a platinum content of 1000 ppm. The mixture was stirred at 1200 rpm for 45 min. Component A was then obtained by mixing 55 parts of a vinyl silicone oil with a content of 0.3% and a viscosity of 850 mPa. s vinyl silicone oil, 12 parts, hydrogen content 0.6%, viscosity 950 mPa 4 parts of hydrogen-containing silicone oil, 4 parts of fumed silica with a specific surface area of 180 m² / g and a particle size of 16 nm, 8 parts of flame-retardant microcapsules, and 0.08 parts of tetramethyltetravinylcyclotetrasiloxane are mixed evenly and stirred at 1500 rpm for 40 min to obtain component B. Component A and component B are mixed evenly at a mass ratio of 1:1 and stirred at 500-800 rpm for 5-10 min. The mixture is then heated to 70℃ to foam and cured for 1 h to obtain silicone foam.
[0032] Comparative Example 1: The only difference between Comparative Example 1 and Example 1 is that flame-retardant microcapsules are not used; the rest of the preparation process is basically the same as that of Example 1.
[0033] Comparative Example 2: Preparation of silicone foam: By weight, 65 parts of silicone foam with a vinyl content of 0.2% and a viscosity of 900 mPa are added. Component A is obtained by mixing 10 parts of vinyl silicone oil, 10 parts of hydroxyl silicone oil, 5 parts of hydrophobic fumed silica with a particle size of 20 nm and a specific surface area of 150 m² / g, and 0.02 parts of a chloroplatinic acid-vinylsiloxane complex with a platinum content of 2000 ppm. The mixture is stirred at 1200 rpm for 40 min. Component A is then obtained by mixing 60 parts of a vinyl silicone oil with a content of 0.4% and a viscosity of 750 mPa. s vinyl silicone oil, 15 parts, hydrogen content 0.8%, viscosity 600 mPa 5 parts of hydrogen-containing silicone oil, 5 parts of hydrophobic fumed silica with a specific surface area of 150 m² / g and a particle size of 20 nm, 30 parts of aluminum hydroxide, and 0.1 parts of ethynylcyclohexanol are mixed evenly and stirred at 1000 rpm for 35 min to obtain component B. Component A and component B are mixed evenly at a mass ratio of 1:1 and stirred at 500 rpm for 6 min. The mixture is then heated to 65℃ to foam and cured for 1 h to obtain silicone foam.
[0034] Comparative Example 3: Preparation of flame-retardant microcapsules with melamine-formaldehyde resin as the single-layer shell material: (1) By mass, 1 part graphene and 6 parts polyvinylpyrrolidone were mixed, 60 parts deionized water were added, and the mixture was ultrasonically dispersed to obtain a graphene dispersion. (2) Add 0.6 parts of triethanolamine to 20 parts of formaldehyde solution by mass, adjust the pH value to 8.0, stir, heat to 40°C, add 10 parts of melamine and stir to dissolve, heat to 85°C and keep warm for reaction, after the reaction is completed, cool to room temperature, add dilute hydrochloric acid to adjust the pH value to 7.0, and obtain melamine formaldehyde prepolymer; (3) By mass, 25 parts of melamine-formaldehyde prepolymer were added to 10 parts of primary microspheres, 0.2 parts of styrene-maleic anhydride copolymer were added, and ammonia was added to adjust the pH to 8.0 before curing. After centrifugation, the mixture was dried at 60°C to obtain flame-retardant microcapsules with melamine-formaldehyde resin as the single-layer shell material.
[0035] Preparation of silicone foam: By weight, 65 parts of silicone foam with a vinyl content of 0.2% and a viscosity of 900 mPa are added. Component A is obtained by mixing 10 parts of vinyl silicone oil, 10 parts of hydroxyl silicone oil, 5 parts of hydrophobic fumed silica with a particle size of 20 nm and a specific surface area of 200 m² / g, and 0.02 parts of a chloroplatinic acid-vinylsiloxane complex with a platinum content of 2000 ppm. The mixture is stirred at 1200 rpm for 40 min. Component A is then obtained by mixing 60 parts of a vinyl silicone oil with a content of 0.4% and a viscosity of 750 mPa. s vinyl silicone oil, 15 parts, hydrogen content 0.8%, viscosity 600 mPa 5 parts of hydrogen-containing silicone oil, 5 parts of hydrophobic fumed silica with a specific surface area of 150 m² / g and a particle size of 20 nm, 8 parts of flame-retardant microcapsules, and 0.1 parts of ethynylcyclohexanol were mixed evenly and stirred at 1000 rpm for 35 min to obtain component B. Component A and component B were mixed evenly at a mass ratio of 1:1 and stirred at 500 rpm for 6 min. The mixture was then heated to 65℃ to foam and cured for 1 h to obtain silicone foam.
[0036] The performance of the silicone foams prepared in Examples 1-5 and Comparative Examples 1-3 was tested, and the results are shown in Table 1.
[0037] Table 1: Performance test results of the silicone foams prepared in Examples 1-5 and Comparative Examples 1-3
[0038] The test results from Examples 1-5 and Comparative Example 1 show that the silicone foam prepared in Examples 1-5 of this invention has excellent flame retardant properties (LOI≥32%), good mechanical properties and high and low temperature resistance. The LOI of the silicone foam without flame retardant microcapsules is significantly reduced, and the flame retardant rating is lowered.
[0039] As can be seen from the data of Examples 1-5 and Comparative Example 2, when aluminum hydroxide is used as a flame retardant, the mechanical properties of the silicone foam prepared by adding 30 parts by weight of aluminum hydroxide decrease.
[0040] As can be seen from the data of Comparative Example 3 of Examples 1-5, the compression set of silicone foam using single-layer flame-retardant microcapsules decreased. Analysis showed that this was because flame-retardant microcapsules using melamine-formaldehyde resin as the single-layer shell material were prone to decomposition and failure at high temperatures.
[0041] In the description of this specification, the references to terms such as "one embodiment / mode," "some embodiments / modes," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment / mode or example is included in at least one embodiment / mode or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment / mode or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments / modes or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments / modes or examples described in this specification, as well as the features of different embodiments / modes or examples.
[0042] It should be noted that in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise expressly specified.
[0043] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features of the invention herein.
Claims
1. An organosilicon foam, characterized in that, The product comprises component A and component B. Component A includes the following raw materials: vinyl silicone oil, hydroxyl silicone oil, fumed silica, and platinum catalyst. Component B includes the following raw materials: vinyl silicone oil, hydrogen-containing silicone oil, fumed silica, flame-retardant microcapsules, and inhibitor. The core material of the flame-retardant microcapsules is graphene, and the inner and outer shell materials are modified acrylic resin and melamine-formaldehyde resin, respectively.
2. The silicone foam according to claim 1, characterized in that, The modified acrylic resin is obtained by reacting methyl methacrylate, ethyl acrylate and KH570 coupling agent.
3. The silicone foam according to claim 1, characterized in that, The vinyl silicone oil has a vinyl content of 0.1%-0.5% and a viscosity of 500-5000 mPa. s; The hydrogen content of the hydrogen-containing silicone oil is 0.5%-1.5%, and the viscosity is 100-1000 mPa. s.
4. The silicone foam according to claim 1, characterized in that, The fumed silica is hydrophobic and has a specific surface area of 150-300 m². 2 / g, with a particle size of 6-20nm.
5. The silicone foam according to claim 1, characterized in that, The platinum catalyst is a chloroplatinic acid-vinylsiloxane complex with a platinum content of 1000-5000 ppm.
6. The silicone foam according to claim 1, characterized in that, The inhibitor is at least one of ethynylcyclohexanol and tetramethyltetravinylcyclotetrasiloxane.
7. The silicone foam according to claim 1, characterized in that, The mass fractions of each raw material in Component A are: 60-80 parts vinyl silicone oil, 5-15 parts hydroxyl silicone oil, 3-8 parts fumed silica, and 0.01-0.05 parts platinum catalyst; the mass fractions of each raw material in Component B are: 50-70 parts vinyl silicone oil, 10-20 parts hydrogen-containing silicone oil, 3-8 parts fumed silica, 5-10 parts flame-retardant microcapsules, and 0.05-0.2 parts inhibitor.
8. The silicone foam according to claim 1, characterized in that, The flame-retardant microcapsules are prepared through the following process: S101, graphene and polyvinylpyrrolidone are mixed and ultrasonically dispersed to obtain a graphene dispersion; S102, methyl methacrylate, ethyl acrylate and anhydrous ethanol are mixed, KH570 coupling agent is added, benzoyl peroxide is added under nitrogen protection, and the mixture is heated to 80-85℃ to obtain a modified acrylic resin prepolymer. S103, add triethanolamine to formaldehyde solution, adjust pH to 8.0-9.0, stir, heat to 40-50℃, add melamine and stir to dissolve, heat to 80-90℃ and keep the reaction at this temperature, after the reaction is complete, cool to room temperature, add dilute hydrochloric acid to adjust pH to 6.5-7.0, and obtain melamine-formaldehyde prepolymer; S104, modified acrylic resin prepolymer is added dropwise to graphene dispersion, sodium dodecylbenzenesulfonate is added for emulsification and dispersion, and the mixture is heated at 70-80℃ for 3-4 hours to obtain primary microspheres; S105, melamine-formaldehyde prepolymer was added dropwise to primary microspheres, followed by styrene-maleic anhydride copolymer. After adjusting the pH to 8.0-8.5, the mixture was cured, centrifuged, and dried at 50-70℃ to obtain flame-retardant microcapsules.
9. A method for preparing the silicone foam according to any one of claims 1-8, characterized in that, Includes the following steps: Preparation of component A: Vinyl silicone oil, hydroxyl silicone oil, fumed silica, and platinum catalyst were mixed evenly to obtain component A; Preparation of Component B: Vinyl silicone oil, hydrogen-containing silicone oil, fumed silica, flame-retardant microcapsules, and inhibitor are mixed evenly to obtain Component B; Foaming and curing: Mix components A and B evenly, heat to 60-80℃ to foam and cure for 1-2 hours to obtain silicone foam.
10. The method for preparing the organosilicon foam according to claim 9, characterized in that, The flame-retardant microcapsules are prepared through the following process: S101, graphene and polyvinylpyrrolidone are mixed and ultrasonically dispersed to obtain a graphene dispersion; S102, methyl methacrylate, ethyl acrylate and anhydrous ethanol are mixed, KH570 coupling agent is added, benzoyl peroxide is added under nitrogen protection, and the mixture is heated to 80-85℃ to obtain a modified acrylic resin prepolymer. S103, add triethanolamine to formaldehyde solution, adjust pH to 8.0-9.0, stir, heat to 40-50℃, add melamine and stir to dissolve, heat to 80-90℃ and keep the reaction at this temperature, after the reaction is complete, cool to room temperature, add dilute hydrochloric acid to adjust pH to 6.5-7.0, and obtain melamine-formaldehyde prepolymer; S104, modified acrylic resin prepolymer is added dropwise to graphene dispersion, sodium dodecylbenzenesulfonate is added for emulsification and dispersion, and the mixture is heated at 70-80℃ for 3-4 hours to obtain primary microspheres; S105, melamine-formaldehyde prepolymer was added dropwise to primary microspheres, followed by styrene-maleic anhydride copolymer. After adjusting the pH to 8.0-8.5, the mixture was cured, centrifuged, and dried at 50-70℃ to obtain flame-retardant microcapsules.