High-transparency silicone rubber composite material and preparation method thereof

Abstract

The invention relates to the field of organic polymer composite materials, in particular to a high-transparency silicone rubber composite material and a preparation method thereof.The high-transparency silicone rubber composite material is prepared from, by mass, 50-55 parts of modified vinyl-terminated polydimethylsiloxane, 40-45 parts of vinyl-terminated polydimethylsiloxane, 3-5 parts of a modified chain extension cross-linking agent and 3-5 parts of a hydrogen-containing silicone oil cross-linking agent, by innovatively adopting the surface-modified organic silicon resin and the modified chain extension cross-linking agent, the technical problem that high filling amount and high transparency are difficult to consider at the same time is successfully solved, and compared with the prior art, the high-transparency organic silicon resin has the advantages of excellent optical transparency and mechanical strength, high transparency and high transparency, and can be used for preparing high-transparency organic silicon resin and high-transparency organic silicon resin composite materials for the high-transparency organic silicon resin composite materials for the high-transparency organic silicon resin composite materials for the high-transparency organic silicon resin composite materials. And an intelligent self-repairing function is also shown, the service life of the product is effectively prolonged, and the method has a wide application prospect in the fields of high-end optical packaging, flexible electronics, medical instruments and the like.

Description

Technical Field

[0001] This invention relates to the field of organic polymer composite materials, and more particularly to a highly transparent silicone rubber composite material and its preparation method. Background Technology

[0002] High-transparency silicone rubber composite material is a special elastomer material with high light transmittance and low haze in the visible light range. It is made by using polysiloxane as the matrix, combining various additives and adopting specific processing technology. Due to its combination of the excellent properties of silicone rubber such as high and low temperature resistance, weather resistance, physiological inertness, and electrical insulation, as well as its excellent optical transparency, this type of material plays an irreplaceable role in high-end fields.

[0003] However, in existing technologies, traditional materials typically require the addition of reinforcing fillers such as silica to achieve sufficient mechanical strength. However, there are differences in refractive index and compatibility issues between the fillers and the silicone rubber matrix, which can easily lead to agglomeration and strong light scattering, resulting in increased haze and decreased transparency. At the same time, the phenyl groups introduced to increase the refractive index to meet the needs of specific optical devices often exacerbate the risk of yellowing under ultraviolet light aging, affecting the optical stability of the material in long-term use. In addition, conventional silicone rubber cannot self-repair after being subjected to micro or macro damage, which reduces its service life and reliability in vulnerable scenarios such as precision optics and flexible electronics.

[0004] Therefore, based on the relevant technologies mentioned above, there is an urgent need to develop a highly transparent silicone rubber composite material and its preparation method. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a highly transparent silicone rubber composite material and its preparation method to solve the problems in the prior art.

[0006] To achieve the above objectives, the present invention provides a highly transparent silicone rubber composite material and its preparation method.

[0007] A highly transparent silicone rubber composite material is composed of the following components in parts by weight: 50-55 parts of modified vinyl-terminated polydimethylsiloxane, 40-45 parts of vinyl-terminated polydimethylsiloxane, 3-5 parts of modified chain extender crosslinking agent, 3-5 parts of hydrogen-containing silicone oil crosslinking agent, 0.05-0.1 parts of inhibitor, and 0.01-0.05 parts of platinum catalyst; The modified vinyl-terminated polydimethylsiloxane is a vinyltrimethoxysilane-modified vinyl-terminated polydimethylsiloxane.

[0008] Preferably, the preparation steps of the modified vinyl-terminated polydimethylsiloxane are as follows: Modified organosilicon resin and vinyltrimethoxysilane were added to vinyl-terminated polydimethylsiloxane, heated to 20-30℃, stirred at 300-500 rpm for 5-10 min, and the reactants were placed in a high-speed shear press, heated to 50-60℃, depressurized to -0.095 MPa, and sheared at 2000-3000 rpm for 60-70 min. After shearing, the temperature was lowered to 20-30℃ to obtain modified vinyl-terminated polydimethylsiloxane. The synergistic effect of high-speed shearing and vacuum degassing significantly improves the compatibility and dispersion stability of the filler, laying a solid foundation for the preparation of highly transparent and high-strength silicone rubber composite materials.

[0009] Preferably, the mass ratio of the vinyl-terminated polydimethylsiloxane, the modified silicone resin, and the vinyltrimethoxysilane is 1:0.25-0.3:0.01-0.015.

[0010] Preferably, the preparation steps of the modified organosilicon resin are as follows: Step B1: Add nano-silica to anhydrous ethanol, stir for 10-20 min at 200-300 rpm, transfer to an ultrasonic cell disruptor at 300-500 W, cool to -5-0℃, react for 30-40 min, and the reaction is complete, forming a silica ethanol sol. Step B2: Add methyltrimethoxysilane and phenyltrimethoxysilane to anhydrous ethanol solution, mix well, add 13 mol / L ammonia water, adjust pH to 8-9, add deionized water, stir for 5-10 min, and after stirring is complete, obtain silane precursor solution; Step B3: Add silica ethanol sol to the silane precursor solution, heat to 58-62℃, stir at 300-500 rpm for 13-15 hours until the reaction is complete, cool to 20-30℃, centrifuge and wash, vacuum dry, and pass through a 500-mesh sieve to obtain modified organosilicon resin. By using an ultrasonic-assisted dispersion and precise catalysis system, a dense silicone resin shell with excellent interfacial compatibility was constructed in situ on the surface of nano-silica. This process effectively avoids filler agglomeration and significantly improves its dispersibility and binding force in the matrix, providing a key material basis for the preparation of highly transparent and high-strength silicone rubber composites.

[0011] Preferably, the mass ratio of nano-silica to anhydrous ethanol in step B1 is 1:20-25.

[0012] Preferably, the mass ratio of methyltrimethoxysilane, phenyltrimethoxysilane, anhydrous ethanol and deionized water in step B2 is 1:0.8-1:6-8:0.8-1.2; The mass ratio of silica ethanol sol to silane precursor solution in step B3 is 1:2-3.

[0013] Preferably, the preparation steps of the modified chain extender / crosslinker are as follows: Step C1: Add 2,2'-dithiodiethylamine hydrochloride to anhydrous dimethylformamide solvent, heat to 20-30℃, stir for 5-10 min, add mercaptoacetic acid and 4-dimethylaminopyridine, stir for 10-15 min, and the reaction is complete to obtain a mixture; Step C2: Under a nitrogen atmosphere, add dicyclohexylcarbodiimide to the mixture, cool to 0-5℃, stir for 15-25 min, heat to 35-45℃, stir for 10-14 h at a speed of 200-400 rpm, and when the reaction is complete, cool to 20-30℃, filter and wash, distill under reduced pressure, purify and dry to obtain the modified chain extender crosslinking agent; By using nitrogen protection and precise temperature control, side reactions such as thiol oxidation are effectively suppressed, ensuring the integrity and high purity of the dynamic disulfide bond structure. Combined with a multi-step fine purification process, the resulting chain extender crosslinking agent can build a stable and uniform dynamic crosslinking network for silicone rubber, significantly improving its self-healing efficiency and mechanical toughness.

[0014] Preferably, the mass ratio of 2,2'-dithiodiethylamine hydrochloride, mercaptoacetic acid, and 4-dimethylaminopyridine in step C1 is 1:2-2.5:0.05-0.1; The mass ratio of dicyclohexylcarbodiimide to the mixture in step C2 is 1:2-4.

[0015] A method for preparing a highly transparent silicone rubber composite material, comprising the following steps: Step S1: Add the modified vinyl-terminated polydimethylsiloxane to the vinyl-terminated polydimethylsiloxane, reduce the pressure to -0.09MPa, stir for 20-30 min at a speed of 500-600 rpm, add the modified chain extender crosslinking agent, stir for 15-20 min, add the hydrogen-containing silicone oil crosslinking agent, inhibitor and platinum catalyst, stir for 300-350 rpm for 30-35 min to obtain the rubber compound; Step S2: Pour the rubber compound into the mold, degas under vacuum for 5-10 minutes, transfer to an oven, heat to 70-90℃, keep at that temperature for 50-70 minutes, heat to 110-130℃, keep at that temperature for 1.5-2.5 hours, the reaction is complete, cool to 20-30℃, and you will get a high-transparency silicone rubber composite material. By employing a stepwise mixing and segmented curing process under vacuum, the uniform dispersion of each component and the full construction of the cross-linked network were effectively ensured, successfully resolving the issues of internal air bubbles and interfacial compatibility. The resulting silicone rubber composite material exhibits excellent optical transparency, superior mechanical properties, and stable self-healing capabilities, resulting in a significant improvement in overall performance.

[0016] Preferably, the mass ratio of the modified vinyl-terminated polydimethylsiloxane, the modified chain extender crosslinker, the hydrogen-containing silicone oil crosslinker, the inhibitor, and the platinum catalyst in step S1 is 1:0.72-0.9:0.05-0.1:0.05-0.1:0.001-0.02:0.0002-0.001.

[0017] The beneficial effects of this invention are: This invention relates to a highly transparent silicone rubber composite material and its preparation method. By innovatively employing surface-modified organosilicon resin and a modified chain extender / crosslinker, this invention successfully solves the technical challenge of simultaneously achieving high filler content and high transparency. The unique material design combined with an optimized preparation process achieves nanoscale dispersion and perfect interfacial bonding of the filler in the matrix, while simultaneously constructing a stable and reversible dynamic crosslinking network. The resulting silicone rubber composite material not only possesses excellent optical transparency and mechanical strength but also exhibits intelligent self-healing capabilities, effectively extending product lifespan. This technology overcomes the performance limitations of traditional silicone rubber and has broad application prospects in high-end optical packaging, flexible electronics, and medical devices. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0019] Example 1: Preparation steps of modified vinyl-terminated polydimethylsiloxane: S1: Add 30g of modified silicone resin and 1g of vinyltrimethoxysilane to 100g of vinyl-terminated polydimethylsiloxane, stir at 500rpm for 5min, place in a high-speed shear press, heat to 60℃, depressurize to -0.095MPa, shear at high speed for 70min at 2000rpm, and after shearing, cool to 20℃ to obtain modified vinyl-terminated polydimethylsiloxane.

[0020] Example 2: Preparation steps of modified vinyl-terminated polydimethylsiloxane: 27.5g of modified silicone resin and 1.25g of vinyltrimethoxysilane were added to 100g of vinyl-terminated polydimethylsiloxane. The mixture was stirred at 400rpm for 8min. The mixture was then placed in a high-speed shear press, heated to 55℃, depressurized to -0.095MPa, and sheared at high speed for 65min at 2500rpm. After shearing, the mixture was cooled to 25℃ to obtain the modified vinyl-terminated polydimethylsiloxane.

[0021] Example 3: Preparation steps of modified vinyl-terminated polydimethylsiloxane: 25g of modified silicone resin and 1.5g of vinyltrimethoxysilane were added to 100g of vinyl-terminated polydimethylsiloxane. The mixture was stirred at 300 rpm for 10 minutes. The mixture was then placed in a high-speed shear press, heated to 50°C, depressurized to -0.095 MPa, and sheared at high speed for 60 minutes at 2000 rpm. After shearing, the mixture was cooled to 30°C to obtain the modified vinyl-terminated polydimethylsiloxane. Example 4: Preparation steps of modified organosilicon resin: S1: Add 10g of nano-silica to 200g of anhydrous ethanol, stir at 250rpm for 20min, transfer to an ultrasonic cell disruptor, power 300W, cool to 0℃, react for 40min, and the reaction is complete to obtain silica ethanol sol. S2: Add 100g of methyltrimethoxysilane and 80g of phenyltrimethoxysilane to 600g of anhydrous ethanol solution, mix well, add 13mol / L ammonia water to adjust the pH to 8-9, add 80g of deionized water, stir at 200rpm for 10min, and after stirring is complete, obtain silane precursor solution. S3: Add 100g of silica ethanol sol to 200g of silane precursor solution, heat to 62℃, stir at 500rpm for 12h until the reaction is complete, cool to 30℃, centrifuge and wash, vacuum dry, and pass through a 500-mesh sieve to obtain modified organosilicon resin.

[0022] Example 5: Preparation steps of modified organosilicon resin: S1: Add 10g of nano-silica to 225g of anhydrous ethanol, stir at 300rpm for 20min, transfer to an ultrasonic cell disruptor, power 400W, cool to 0℃, react for 40min, and the reaction is complete to obtain silica ethanol sol. S2: Add 100g of methyltrimethoxysilane and 90g of phenyltrimethoxysilane to 700g of anhydrous ethanol solution, mix well, add 13mol / L ammonia water to adjust the pH to 8-9, add 100g of deionized water, stir at 300rpm for 8min, and after stirring is complete, obtain silane precursor solution. S3: Add 100g of silica ethanol sol to 250g of silane precursor solution, heat to 60℃, stir at 450rpm for 13h until the reaction is complete, cool to 25℃, centrifuge and wash, vacuum dry, and pass through a 500-mesh sieve to obtain modified organosilicon resin.

[0023] Example 6: Preparation steps of modified organosilicon resin: S1: Add 10g of nano-silica to 250g of anhydrous ethanol, stir at 300rpm for 10min, transfer to an ultrasonic cell disruptor, power 500W, cool to -5℃, react for 30min, the reaction is complete, silica ethanol sol is formed. S2: Add 100g of methyltrimethoxysilane and 100g of phenyltrimethoxysilane to 800g of anhydrous ethanol solution, mix well, add 13mol / L ammonia water to adjust the pH to 8-9, add 120g of deionized water, stir at 300rpm for 5min, and after stirring is complete, obtain silane precursor solution. S3: Add 100g of silica ethanol sol to 200g of silane precursor solution, heat to 58℃, stir at 400rpm for 14h until the reaction is complete, cool to 20℃, centrifuge and wash, vacuum dry, and pass through a 500-mesh sieve to obtain modified organosilicon resin.

[0024] Example 7: Preparation steps of modified chain extender crosslinking agent: S1: Add 10g of 2,2'-dithiodiethylamine hydrochloride to 100ml of anhydrous dimethylformamide solvent, heat to 30℃, stir at 300rpm for 10min, add 20g of mercaptoacetic acid and 1g of 4-dimethylaminopyridine, stir and react for 10min until the reaction is complete, and obtain a mixture. S2: Under a nitrogen atmosphere, 10g of dicyclohexylcarbodiimide was added to 40g of the mixture, cooled to 5°C, stirred at 400rpm for 15min, heated to 35°C, and stirred for 14h until the reaction was complete. The mixture was then cooled to 20°C, filtered, washed, and purified by vacuum distillation to obtain the modified chain extender and crosslinker.

[0025] Example 8: Preparation steps of modified chain extender crosslinking agent: S1: Add 10g of 2,2'-dithiodiethylamine hydrochloride to 100ml of anhydrous dimethylformamide solvent, heat to 25℃, stir at 350rpm for 8min, add 22.5g of mercaptoacetic acid and 0.75g of 4-dimethylaminopyridine, stir for 12min, and the reaction is complete to obtain a mixture; S2: Under a nitrogen atmosphere, 10g of dicyclohexylcarbodiimide was added to 30g of the mixture, cooled to 2℃, stirred at 300rpm for 20min, heated to 40℃, and stirred for 12h until the reaction was complete. The mixture was then cooled to 25℃, filtered, washed, and purified by vacuum distillation to obtain the modified chain extender and crosslinker.

[0026] Example 9: Preparation steps of modified chain extender crosslinking agent: S1: Add 10g of 2,2'-dithiodiethylamine hydrochloride to 100ml of anhydrous dimethylformamide solvent, heat to 20℃, stir at 400rpm for 5min, add 25g of mercaptoacetic acid and 0.5g of 4-dimethylaminopyridine, stir for 15min, and the reaction is complete to obtain a mixture; S2: Under a nitrogen atmosphere, 10g of dicyclohexylcarbodiimide was added to 20g of the mixture, cooled to 0℃, stirred at 200rpm for 25min, heated to 45℃, and stirred for 10h until the reaction was complete. The mixture was then cooled to 30℃, filtered, washed, and purified by vacuum distillation to obtain the modified chain extender and crosslinker.

[0027] Example 10: A method for preparing a highly transparent silicone rubber composite material S1: Add 100g of modified vinyl-terminated polydimethylsiloxane to 90g of vinyl-terminated polydimethylsiloxane, reduce the pressure to -0.09MPa, stir at 500rpm for 30min, add 5g of modified chain extender crosslinking agent, stir for 20min, add 5g of hydrogen-containing silicone oil crosslinking agent, 0.2g of inhibitor and 0.02g of platinum catalyst, reduce the speed to 300rpm, stir for 35min to obtain the rubber compound; S2: Pour the rubber compound into the mold, vacuum degas for 10 minutes, transfer to an oven, heat to 90°C, keep warm for 50 minutes, heat to 130°C, keep warm for 1.5 hours, the reaction is complete, cool to 20°C, and obtain a high-transparency silicone rubber composite material.

[0028] Example 11: A method for preparing a highly transparent silicone rubber composite material S1: Add 100g of modified vinyl-terminated polydimethylsiloxane to 81g of vinyl-terminated polydimethylsiloxane, reduce the pressure to -0.09MPa, stir at 550rpm for 25min, add 7.5g of modified chain extender crosslinker, stir for 18min, add 7.5g of hydrogen-containing silicone oil crosslinker, 0.15g of inhibitor and 0.05g of platinum catalyst, reduce the speed to 325rpm, stir for 33min to obtain the rubber compound; S2: Pour the rubber compound into the mold, vacuum degas for 8 minutes, transfer to an oven, heat to 80°C, keep warm for 60 minutes, heat to 120°C, keep warm for 2 hours, the reaction is complete, cool to 25°C, and obtain a high-transparency silicone rubber composite material.

[0029] Example 12: A method for preparing a highly transparent silicone rubber composite material S1: Add 100g of modified vinyl-terminated polydimethylsiloxane to 72g of vinyl-terminated polydimethylsiloxane, reduce the pressure to -0.09MPa, stir at 600rpm for 20min, add 10g of modified chain extender crosslinking agent, stir for 15min, add 10g of hydrogen-containing silicone oil crosslinking agent, 0.1g of inhibitor and 0.1g of platinum catalyst, reduce the speed to 350rpm, stir for 30min to obtain the rubber compound; Step S2: Pour the rubber compound into the mold, vacuum degas for 5 minutes, transfer to an oven, heat to 70°C, keep at that temperature for 70 minutes, heat to 110°C, keep at that temperature for 2.5 hours until the reaction is complete, then cool to 30°C to obtain a high-transparency silicone rubber composite material.

[0030] Comparative Example 1: Compared with Example 10, this comparative example did not perform a pressure reduction treatment in the preparation process S1 of a high-transparency silicone rubber composite material. All other steps and parameters were the same, and will not be repeated here. The final result was a high-transparency silicone rubber composite material.

[0031] Comparative Example 2: Compared with Example 10, this comparative example only replaces the "hydrogen-containing silicone oil crosslinking agent" with the "peroxide crosslinking agent". All other steps and parameters are the same, and will not be repeated in this comparative example. The final result is a high-transparency silicone rubber composite material.

[0032] Comparative Example 3: Compared with Example 10, this comparative example only omits hollow degassing in the preparation process S2 of a high-transparency silicone rubber composite material. All other steps and parameters are the same, and will not be repeated here. The final result is a high-transparency silicone rubber composite material.

[0033] Comparative Example 4: Compared with Example 10, in the preparation process S2 of a high-transparency silicone rubber composite material, the oven temperature was raised to 110°C, and the rubber compound was transferred to the oven for reaction for 4 hours. The remaining steps and parameters were the same, and will not be repeated in this comparative example. Finally, a high-transparency silicone rubber composite material was obtained.

[0034] Performance testing: Density test: Referring to the GB / T533-2008 test standard, using an XS204 electronic densitometer, the composite materials of Examples 10-12 and Comparative Examples 1-4 were cut into 25×25×5mm cubes, added to distilled water, heated to 25℃, and the average value was taken for three measurements.

[0035] Flame retardancy test: According to the GB / T2408-2021 test standard, the FTT cone calorimeter was used to take the composite materials of Examples 10-12 and Comparative Examples 1-4, cut them into 125×13×3mm pieces, burn them vertically for 10s, and record the self-extinguishing time and molten droplets.

[0036] Table 1 Test Results of Examples and Comparative Examples

[0037] Tensile strength and elongation at break tests: Referring to the GB / T528-2009 testing standard, a universal testing machine was used. Composite materials from Examples 10-12 and Comparative Examples 1-4 were cut into 50×10×2mm pieces and placed in the testing machine. The tensile rate was 2mm / min, the temperature was raised to 23℃, and the environment was maintained at 50%RH. The tensile strength was tested, and the formula for calculating the elongation at break is:

[0038] In the formula: ϵ b Elongation at break, expressed as a percentage (%).

[0039] L b : Gauge length at which the specimen breaks, in millimeters (mm).

[0040] L0: The original gauge length of the specimen, in millimeters (mm).

[0041] Tear strength test: Using a universal testing machine, composite materials from Examples 10-12 and Comparative Examples 1-4 were tested. Right-angled tear specimens were used, symmetrically clamped in a fixture, and stretched at a constant speed of 500 mm / min until the specimen was completely torn. The maximum force value during the test was recorded. The tear strength was calculated using the formula:

[0042] 1. Where TS is the tear strength (kN / m), F is the maximum force (N), and d is the sample thickness (mm).

[0043] Self-repair efficiency test: The universal tensile testing machine was used in accordance with the GB / T528-2009 testing standard. The composite materials of Examples 10-12 and Comparative Examples 1-4 were taken respectively, and six parallel specimens were prepared for each group of samples using standard dumbbell-shaped specimens.

[0044] 2. Three of the specimens were used as the reference group and their tensile strength was directly tested. For the other three specimens, a through cut was made in the middle of the parallel section of the specimen with a sharp blade. The cut surfaces were then rejoined and repaired by heat treatment at 80°C for 2 hours. Their tensile strength was then tested. 3. Calculation formula:

[0045] Table 2. Self-healing efficiency test results of the examples and comparative examples

[0046] *Note: Due to the incompatibility of the crosslinking system, the material in Comparative Example 2 was not fully cured, and the test values ​​only represent its performance in the incompletely cured state.

[0047] Light transmittance and haze test: In accordance with the GB / T2410-2008 testing standard, an integrating sphere haze meter was used. 1. Take the composite materials of Examples 10-12 and Comparative Examples 1-4 respectively, cut them into 50mm×50mm×1mm samples, clean the surface and fix them on the sample holder; 2. In an environment with a temperature of 23±2℃ and a humidity of 50±10%, using a standard C light source, measure the total transmitted light flux T2, the instrument scattered light flux T1, the sample scattered light flux T4, and the sample and instrument scattered light flux T3 respectively. 3. Calculate the light transmittance: ; 4. Calculate the haze:

[0048] Table 3. Transmittance and Haze Test Results of Examples and Comparative Examples

[0049] Data Analysis: As can be seen from Tables 1-3, the high-transparency silicone rubber composite material prepared by this invention has excellent synergistic improvement in optical transparency, mechanical strength, flame retardancy and self-healing function.

[0050] Comparative Example 1, which did not undergo pressure reduction during preparation, had the lowest density but significantly reduced overall performance. This was because the lack of vacuum degassing resulted in a large number of microbubbles remaining in the adhesive. These bubbles, acting as light scattering centers and stress concentration points, severely weakened the optical uniformity and mechanical integrity of the material. At the same time, the bubbles provided channels and oxygen for the combustion process, leading to unqualified flame retardant performance. Comparative Example 2 shows that when the hydrogen-containing silicone oil crosslinking agent was replaced with a peroxide crosslinking agent, its curing mechanism was completely incompatible with the addition-type system. The material yellowed severely, and its tensile strength and tear strength dropped sharply. Moreover, its self-healing function was completely lost. This is because the peroxide crosslinking triggered the breakage of the siloxane main chain and oxidation side reaction through the free radical mechanism, which could not build a dynamic disulfide bond network. At the same time, the crosslinking structure defects led to the overall deterioration of the material's mechanical properties and optical transparency. Comparative Example 3, due to the lack of vacuum degassing in the post-casting stage, has macroscopic bubble defects inside, resulting in a significant reduction in light transmittance and mechanical properties, and an increase in haze. This is because the bubbles entrained during the casting process were not removed, forming stable light scattering sources and mechanical weak points after curing. At the same time, the bubbles hinder the uniform formation of the cross-linking network, leading to a decline in the overall performance of the material. Comparative Example 4, due to the use of a single-stage 110℃ curing process without a stepped heating procedure, showed a significant deterioration in its self-healing efficiency and mechanical properties. This is because the exchange reaction of the modified chain extender crosslinking agent requires a higher annealing stage to optimize the network distribution. One-step curing cannot achieve the recombination and stabilization of dynamic bonds, resulting in an uneven crosslinking network and failure to achieve synergistic optimal repair capability and mechanical strength.

[0051] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

[0052] This invention is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A highly transparent silicone rubber composite material, characterized in that, It is composed of the following components in parts by weight: 50-55 parts of modified vinyl-terminated polydimethylsiloxane, 40-45 parts of vinyl-terminated polydimethylsiloxane, 3-5 parts of modified chain extender crosslinking agent, 3-5 parts of hydrogen-containing silicone oil crosslinking agent, 0.05-0.1 parts of inhibitor, and 0.01-0.05 parts of platinum catalyst. The modified vinyl-terminated polydimethylsiloxane is a vinyltrimethoxysilane-modified vinyl-terminated polydimethylsiloxane.

2. The high-transparency silicone rubber composite material according to claim 1, characterized in that, The preparation steps of the modified vinyl-terminated polydimethylsiloxane are as follows: Modified organosilicon resin and vinyltrimethoxysilane were added to vinyl-terminated polydimethylsiloxane, heated to 20-30℃, and stirred for 5-10 minutes. The reactants were then placed in a high-speed shear press, heated to 50-60℃, depressurized to -0.095MPa, and sheared at high speed for 60-70 minutes. After shearing, the temperature was lowered to 20-30℃ to obtain modified vinyl-terminated polydimethylsiloxane.

3. The high-transparency silicone rubber composite material according to claim 2, characterized in that, The mass ratio of the vinyl-terminated polydimethylsiloxane, modified silicone resin, and vinyltrimethoxysilane is 1:0.25-0.3:0.01-0.

015.

4. The high-transparency silicone rubber composite material according to claim 2, characterized in that, The preparation steps of the modified organosilicon resin are as follows: Step B1: Add nano-silica to anhydrous ethanol, stir for 10-20 min, transfer to an ultrasonic cell disruptor, power 300-500W, cool to -5-0℃, react for 30-40 min, the reaction is complete, and silica ethanol sol is obtained. Step B2: Add methyltrimethoxysilane and phenyltrimethoxysilane to anhydrous ethanol solution, mix well, add 13 mol / L ammonia water, adjust pH to 8-9, add deionized water, stir for 5-10 min, and after stirring is complete, obtain silane precursor solution; Step B3: Add silica ethanol sol to the silane precursor solution, heat to 58-62℃, stir and react for 13-15 hours. After the reaction is complete, cool to 20-30℃, centrifuge and wash, vacuum dry, and pass through a 500-mesh sieve to obtain modified organosilicon resin.

5. The high-transparency silicone rubber composite material according to claim 4, characterized in that, The mass ratio of nano-silica to anhydrous ethanol in step B1 is 1:20-25.

6. The high-transparency silicone rubber composite material according to claim 4, characterized in that, The mass ratio of methyltrimethoxysilane, phenyltrimethoxysilane, anhydrous ethanol, and deionized water in step B2 is 1:0.8-1:6-8:0.8-1.

2. The mass ratio of silica ethanol sol to silane precursor solution in step B3 is 1:2-3.

7. The high-transparency silicone rubber composite material according to claim 1, characterized in that, The preparation steps of the modified chain extender and crosslinker are as follows: Step C1: Add 2,2'-dithiodiethylamine hydrochloride to anhydrous dimethylformamide solvent, heat to 20-30℃, stir for 5-10 min, add mercaptoacetic acid and 4-dimethylaminopyridine, stir for 10-15 min, and the reaction is complete to obtain a mixture; Step C2: Under a nitrogen atmosphere, add dicyclohexylcarbodiimide to the mixture, cool to 0-5℃, stir for 15-25 min, heat to 35-45℃, stir and react for 10-14 h. After the reaction is complete, cool to 20-30℃, filter and wash, distill under reduced pressure, purify and dry to obtain the modified chain extender crosslinking agent.

8. The high-transparency silicone rubber composite material according to claim 7, characterized in that, In step C1, the mass ratio of 2,2'-dithiodiethylamine hydrochloride, mercaptoacetic acid, and 4-dimethylaminopyridine is 1:2-2.5:0.05-0.

1. The mass ratio of dicyclohexylcarbodiimide to the mixture in step C2 is 1:2-4.

9. A method for preparing a highly transparent silicone rubber composite material according to any one of claims 1-8, characterized in that, The preparation steps are as follows: Step S1: Add the modified vinyl-terminated polydimethylsiloxane to the vinyl-terminated polydimethylsiloxane, reduce the pressure to -0.09MPa, stir for 20-30min, add the modified chain extender crosslinking agent, stir for 15-20min, add the hydrogen-containing silicone oil crosslinking agent, inhibitor and platinum catalyst, reduce the speed, stir for 30-35min, and obtain the rubber compound; Step S2: Pour the rubber compound into the mold, degas under vacuum for 5-10 minutes, transfer it to an oven and heat it in stages to 110-130℃, react for 3-4 hours. After the reaction is complete, cool it down to 20-30℃ to obtain a high-transparency silicone rubber composite material.

10. The method for preparing a high-transparency silicone rubber composite material according to claim 9, characterized in that, The mass ratio of the modified vinyl-terminated polydimethylsiloxane, the modified chain extender crosslinking agent, the hydrogen-containing silicone oil crosslinking agent, the inhibitor, and the platinum catalyst in step S1 is 1:0.72-0.9:0.05-0.1:0.05-0.1:0.001-0.02:0.0002-0.001.

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