A protective wear-resistant long-life silicone rubber and its preparation method

Abstract

The present invention relates to the field of silicone rubber technology, specifically a protective wear-resistant and long-life silicone rubber and a preparation method thereof. The silicone rubber includes the following components by weight: 95-105 parts of base rubber, 30-50 parts of fumed silica, 3-5 parts of hydroxy silicone oil, 30-50 parts of aluminum hydroxide, 20-40 parts of flame retardant, 10-20 parts of composite graphene, 2-8 parts of silane coupling agent, and 0.6-2.2 parts of vulcanizing agent. The present invention is prepared by using methyl vinyl silicone rubber as a base material, fumed silica and composite graphene as reinforcing fillers, aluminum hydroxide and flame retardant as flame retardant fillers, hydroxy silicone oil as a structuring control agent, adding a silane coupling agent and a vulcanizing agent to prepare silicone rubber. The silicone rubber prepared by the present invention has excellent flame retardancy, wear resistance and mechanical properties, and is also resistant to aging, thereby extending its service life.

Description

Technical Field

[0001] The present invention relates to the technical field of silicone rubber, in particular to a protective, wear-resistant and long-life silicone rubber and a preparation method thereof. Background Art

[0002] With the continuous development of industrial manufacturing technology, wear-resistant materials are becoming increasingly important in various industries. Silicone rubber is a high-performance elastic material made from silicon and rubber. It has excellent high-temperature resistance, low-temperature resistance, corrosion resistance, and insulation properties, and is widely used in electronics, automobiles, medical care, aerospace, and other fields. However, traditional silicone rubber has low wear resistance and is susceptible to wear and scratching, resulting in a short lifespan. Silicone rubber lacks elasticity and is prone to cracking and deformation, which affects its service life and effectiveness. It also has poor durability and stability in harsh environments such as high temperatures, acids and alkalis, and is prone to degradation and deterioration. It is easily eroded by oxidation, ultraviolet rays, and chemicals during long-term use, resulting in a decrease in material performance.

[0003] Therefore, we propose a protective wear-resistant and long-life silicone rubber and a preparation method thereof. Summary of the Invention

[0004] The object of the present invention is to provide a protective wear-resistant and long-life silicone rubber and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A method for preparing protective wear-resistant and long-life silicone rubber comprises the following steps:

[0007] The base rubber, fumed silica and hydroxy silicone oil are mixed for 15-30 minutes, and a mixture of aluminum hydroxide, flame retardant, composite graphene and silane coupling agent is added and mixed for another 15-30 minutes. The mixture is subjected to high temperature treatment at 160-170°C for 2-4 hours, cooled to room temperature, and a vulcanizing agent is added and mixed evenly to obtain a rubber mixture; the rubber mixture is subjected to first-stage vulcanization and second-stage vulcanization in sequence to obtain silicone rubber.

[0008] Furthermore, the silicone rubber includes the following components by weight: 95-105 parts of base rubber, 30-50 parts of fumed silica, 3-5 parts of hydroxy silicone oil, 30-50 parts of aluminum hydroxide, 20-40 parts of flame retardant, 10-20 parts of composite graphene, 2-8 parts of silane coupling agent, and 0.6-2.2 parts of vulcanizing agent.

[0009] Furthermore, the base rubber is methyl vinyl silicone rubber.

[0010] Furthermore, the preparation method of the flame retardant is as follows:

[0011] Step (1): adjusting the pH of the Tris-HCl buffer solution to 8.5, adding dopamine hydrochloride and mixing uniformly to obtain a dopamine solution; adding mica powder to the dopamine solution and stirring for 22-24 hours, filtering, washing, and drying to obtain modified mica powder;

[0012] Step (2): uniformly mix alkali lignin, formaldehyde solution and sodium hydroxide, react at 90-100°C for 2-3h, wash, filter and dry to obtain activated lignin; uniformly mix activated lignin, 3-aminopropyltrimethoxysilane, deionized water and anhydrous ethanol, react at 50-60°C for 6-8h, filter, wash and dry to obtain amino lignin;

[0013] Step (3): Evenly mix amino lignin and toluene, add modified mica powder, and reflux at 110-120°C for 15-17 hours to obtain an intermediate; evenly mix the intermediate with DOPO and anhydrous ethanol, and react at 50-60°C for 10-12 hours to obtain a flame retardant.

[0014] In the above technical solution, first, mica powder and dopamine hydrochloride react, dopamine undergoes self-polymerization reaction in a weak alkaline aerobic environment to generate polydopamine, which adheres to the surface of the mica powder. The polar groups such as hydroxyl and amino groups on the polydopamine produce covalent and non-covalent interactions with the mica powder to obtain modified mica powder; lignin is a natural polymer material with a three-dimensional network structure, but its direct use is difficult to meet the flame retardant requirements of the material. By chemically modifying the lignin molecular chain, flame retardant elements such as P, N, and Si are introduced to make the lignin more flame retardant. The flame retardant properties of the material are greatly improved. First, lignin is treated with hydroxymethylation by a hydrothermal method to obtain activated lignin, and then amino groups are introduced through the hydrolysis of 3-aminopropyltrimethoxysilane to obtain amino lignin. Modified mica powder and amino lignin undergo a Schiff base reaction to obtain an intermediate containing a C=N bond. Finally, the C=N bond of the intermediate reacts with the PH bond in DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) to obtain a flame retardant containing P, N, and Si.

[0015] Furthermore, in step (1), the concentration of the Tris-HCl buffer solution is 0.01 mol / L, the concentration of the dopamine solution is 3-5 g / L, and the mass of the mica powder is 1-3% of the mass of the Tris-HCl buffer solution.

[0016] Furthermore, in step (2), the mass concentration of the formaldehyde solution is 37%, and the mass ratio of lignin to the formaldehyde solution and sodium hydroxide is 1:(0.25-0.75):(0.01-0.06).

[0017] Furthermore, in step (2), the mass ratio of activated lignin to 3-glycidylpropyltrimethoxysilane, deionized water and anhydrous ethanol is 1: (0.4-0.6): (3-5): (15-20).

[0018] Furthermore, in the step (3), the mass ratio of amino lignin to toluene and modified mica powder is 1: (8-10): (1-2).

[0019] Furthermore, in step (3), the mass ratio of the intermediate to DOPO and anhydrous ethanol is 1: (0.4-0.8): (10-12).

[0020] Furthermore, the preparation method of the composite graphene is as follows:

[0021] Step S1: ultrasonically dispersing graphene oxide in N,N-dimethylformamide to obtain a graphene dispersion, adding isophorone diisocyanate and dibutyltin diisocyanate under nitrogen protection, reacting at 70-80° C. for 6-8 hours, filtering, washing, and drying to obtain isocyanate-based graphene;

[0022] Step S2: ultrasonically dispersing the isocyanate-based graphene in N,N-dimethylformamide to obtain an isocyanate-based graphene dispersion, adding resveratrol and dibutyltin disilicate under nitrogen protection, reacting at 70-80° C. for 6-8 hours, filtering, washing, and drying to obtain double-bond-containing graphene;

[0023] Step S3: Theobromine and sodium hydroxide solution are mixed evenly to obtain a mixed solution; the double bond-containing graphene is dispersed in N,N-dimethylformamide, added to the mixed solution and mixed evenly, reacted at 70-80° C. for 6-8 hours, filtered, washed, and dried to obtain composite graphene.

[0024] In the above technical scheme, graphene oxide is modified by isophorone diisocyanate to introduce isocyanate groups; then resveratrol is grafted on the surface of the isocyanate-based graphene to introduce double bonds. Finally, an environmentally friendly, low-cost biomass compound, theobromine, is used as a nucleophilic reagent to reduce graphene oxide through a one-step "SN2 nucleophilic reaction". Theobromine is successfully loaded on the surface of the double-bonded graphene to obtain composite graphene. Theobromine (TB) has excellent antioxidant, anti-radiation and free radical scavenging effects. It is a green, environmentally friendly, resource-rich and widely available natural antioxidant that can improve the antioxidant properties of graphene oxide and thus extend the service life of silicone rubber. At the same time, the composite graphene contains carbon-carbon double bonds, which can chemically cross-link with the vinyl group in methyl vinyl silicone rubber raw rubber, thereby increasing the hardness of the silicone rubber.

[0025] Furthermore, in step S1, the concentration of the graphene dispersion is 8-10 mg / mL.

[0026] Furthermore, in step S1, the mass ratio of graphene oxide, isophorone diisocyanate and dibutyltin dilaurate is 1:(4-6):(0.01-0.03).

[0027] Furthermore, in step S2, the concentration of the isocyanate-based graphene dispersion is 5-7 mg / mL.

[0028] Furthermore, in step S2, the mass ratio of isocyanate graphene, resveratrol and dibutyltin dilaurate is 1:(3-5):(0.01-0.03).

[0029] Furthermore, in step S3, the concentration of the mixed solution is 8-10 mg / mL, and the concentration of the sodium hydroxide solution is 30-40 wt %.

[0030] Furthermore, in step S3, the mass of the graphene containing double bonds is 5-10% of the mass of the mixed solution, and the mass of N,N-dimethylformamide is 10-20 times the mass of the graphene containing double bonds.

[0031] Furthermore, the silane coupling agent is 3-glycidylpropyltrimethoxysilane.

[0032] Furthermore, the vulcanizing agent is a dipentadiene vulcanizing agent.

[0033] Furthermore, the mixing temperature is 90-100°C.

[0034] Furthermore, the process conditions of the one-stage vulcanization are: carried out on a flat vulcanizing machine, a temperature of 160-175° C., a molding pressure of 10-15 MPa, and a time of 10-20 min.

[0035] Furthermore, the process conditions of the two-stage vulcanization are: carried out in a blast drying oven, at a temperature of 170-180° C., and for 1-3 hours.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. The present invention discloses a protective, wear-resistant, and long-life silicone rubber and its preparation method. Dopamine is coated on the surface of mica powder through self-polymerization, providing improved adhesion and facilitating bonding with other functional components. Polydopamine and aminolignin then undergo a Schiff base reaction to produce an intermediate containing a C=N bond. The C=N bond of the intermediate reacts with the pH bond of DOPO to ultimately produce a flame retardant containing P, N, and Si, which imparts excellent flame retardancy to the silicone rubber. Mica powder exhibits excellent wear resistance, toughness, insulation, and high-temperature resistance, enhancing the wear resistance and durability of the silicone rubber and improving its stability in harsh environments. Lignin is also an excellent free radical scavenger. The aromatic rings in its molecules conjugate with active groups (such as methoxy, phenolic, carbonyl, and vinyl groups), imparting UV radiation resistance to the lignin. This improves the silicone rubber's aging resistance and extends its service life.

[0038] 2. The present invention provides a protective, wear-resistant, and long-life silicone rubber and a preparation method thereof. Graphene oxide has excellent thermal conductivity, mechanical strength, and good gas barrier properties. By grafting double bonds, it can be better combined with silicone rubber, thereby improving the compatibility between the two, reducing agglomeration, and improving the heat resistance and wear resistance of the silicone rubber. At the same time, the introduction of theobromine can enhance the antioxidant properties of graphene oxide, thereby enhancing the aging resistance of the silicone rubber.

[0039] 3. The present invention provides a protective, wear-resistant, and long-life silicone rubber and its preparation method, which uses methyl vinyl silicone rubber as a base material, fumed silica and composite graphene as reinforcing fillers to increase the strength and hardness of the silicone rubber, aluminum hydroxide and flame retardants as flame retardant fillers, hydroxy silicone oil as a structuring control agent, and silane coupling agents and vulcanizing agents to improve the overall performance of the silicone rubber, thereby producing a heat-vulcanized silicone rubber with excellent flame retardancy, wear resistance, and mechanical strength, suitable for various protective, wear-resistant, and long-life applications. The addition of a flame retardant can replace part of the aluminum hydroxide dosage, and has better flame retardant effects and mechanical properties, thereby improving the flame retardancy and mechanical strength of the silicone rubber; fumed silica and composite graphene as reinforcing fillers can enhance the wear resistance and mechanical strength of the silicone rubber and extend its service life. DETAILED DESCRIPTION

[0040] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0041] In this embodiment, the silane coupling agent is 3-glycidylpropyltrimethoxysilane; the vulcanizing agent is dipentadienyl vulcanizing agent; the methyl vinyl silicone rubber raw rubber is model 110-2, with an average molar mass of 65×10 4 g / mol, sourced from Hesheng Silicon Industry Co., Ltd.; fumed silica: model HL380, sourced from Hubei Huifu Nanomaterials Co., Ltd.; hydroxy silicone oil: hydroxy-terminated polydimethylsiloxane, model JP-107, sourced from Shenzhen Jipeng Silicone and Fluorine Materials Co., Ltd.; aluminum hydroxide: average particle size 1-10 μm, sourced from Zhengzhou Xideli Chemical New Materials Co., Ltd.; mica powder: particle size 1250 mesh, sourced from Shijiazhuang Longcai Mineral Products Co., Ltd.; graphene oxide: model DN-20DY, average thickness 1-3 nm, diameter 4-7 μm, number of layers 2-5, sourced from Zhejiang Zhiti Nano Micro New Materials Co., Ltd.

[0042] In the following examples and comparative examples, 1 part is equal to 10 g.

[0043] Example 1: A method for preparing protective wear-resistant and long-life silicone rubber, comprising the following processes:

[0044] 95 parts of methyl vinyl silicone rubber, 30 parts of fumed silica and 3 parts of hydroxy silicone oil were mixed for 15 minutes, and a mixture of 30 parts of aluminum hydroxide, 20 parts of flame retardant, 10 parts of composite graphene and 2 parts of silane coupling agent was added and mixed for another 15 minutes. The mixture was subjected to high temperature treatment at 160°C for 2 hours, cooled to room temperature, and 0.6 parts of vulcanizing agent was added and mixed evenly to obtain a rubber compound. The rubber compound was subjected to a first stage vulcanization (carried out on a flat vulcanizing press at a temperature of 160°C, a molding pressure of 10 MPa, and a time of 10 minutes) and a second stage vulcanization (carried out in a blast drying oven at a temperature of 170°C and a time of 1 hour) in sequence to obtain silicone rubber.

[0045] The preparation method of the flame retardant is as follows:

[0046] Step (1): adjusting 2000 parts of 0.01 mol / L Tris-HCl buffer solution to pH=8.5, adding dopamine hydrochloride and mixing evenly to obtain a 3 g / L dopamine solution; adding 20 parts of mica powder to the dopamine solution and stirring for 22 hours, filtering, washing, and drying to obtain modified mica powder;

[0047] Step (2): 20 parts of alkali lignin, 5 parts of 37 wt% formaldehyde solution and 0.2 parts of sodium hydroxide are mixed evenly, reacted at 90°C for 2 hours, washed, filtered and dried to obtain activated lignin; 20 parts of activated lignin, 8 parts of 3-aminopropyltrimethoxysilane, 60 parts of deionized water and 300 parts of anhydrous ethanol are mixed evenly, reacted at 50°C for 6 hours, filtered, washed and dried to obtain amino lignin;

[0048] Step (3): uniformly mix 20 parts of amino lignin and 160 parts of toluene, add 20 parts of modified mica powder, and reflux for reaction at 110°C for 15 hours to obtain an intermediate; uniformly mix 20 parts of the intermediate, 8 parts of DOPO, and 200 parts of anhydrous ethanol, and react at 50°C for 10 hours to obtain a flame retardant;

[0049] The preparation method of composite graphene is as follows:

[0050] Step S1: ultrasonically dispersing 10 parts of graphene oxide in N,N-dimethylformamide to obtain an 8 mg / mL graphene dispersion, adding 40 parts of isophorone diisocyanate and 0.1 parts of dibutyltin diosilicate under nitrogen protection, reacting at 70°C for 6 hours, filtering, washing, and drying to obtain isocyanate-based graphene;

[0051] Step S2: ultrasonically dispersing 10 parts of isocyanate-based graphene in N,N-dimethylformamide to obtain a 5 mg / mL isocyanate-based graphene dispersion, adding 30 parts of resveratrol and 0.1 parts of dibutyltin disilicate under nitrogen protection, reacting at 70° C. for 6 hours, filtering, washing, and drying to obtain double-bond-containing graphene;

[0052] Step S3: Theobromine and 30 wt % sodium hydroxide solution were mixed to obtain an 8 mg / mL mixed solution; 10 parts of double-bond graphene were dispersed in 100 parts of N,N-dimethylformamide, 200 parts of the mixed solution were added and mixed evenly, and the mixture was reacted at 70° C. for 6 h. After filtering, washing, and drying, composite graphene was obtained.

[0053] Example 2: A method for preparing protective wear-resistant and long-life silicone rubber, comprising the following processes:

[0054] 100 parts of methyl vinyl silicone rubber, 40 parts of fumed silica and 4 parts of hydroxy silicone oil were mixed for 20 minutes, and a mixture of 40 parts of aluminum hydroxide, 30 parts of flame retardant, 15 parts of composite graphene and 6 parts of silane coupling agent was added and mixed for another 20 minutes. The mixture was subjected to high-temperature treatment at 165°C for 3 hours, cooled to room temperature, and 1 part of vulcanizing agent was added and mixed uniformly to obtain a rubber mixture. The rubber mixture was subjected to a first-stage vulcanization (carried out on a flat vulcanizing press at a temperature of 170°C, a molding pressure of 12 MPa, and a time of 15 minutes) and a second-stage vulcanization (carried out in a forced air drying oven at a temperature of 175°C and a time of 2 hours) to obtain silicone rubber.

[0055] The preparation method of the flame retardant is as follows:

[0056] Step (1): adjusting 1500 parts of 0.01 mol / L Tris-HCl buffer solution to pH=8.5, adding dopamine hydrochloride and mixing evenly to obtain a 4 g / L dopamine solution; adding 30 parts of mica powder to the dopamine solution and stirring for 23 hours, filtering, washing, and drying to obtain modified mica powder;

[0057] Step (2): 20 parts of alkali lignin, 8 parts of 37 wt% formaldehyde solution and 0.8 parts of sodium hydroxide are mixed evenly, reacted at 95°C for 2.5 hours, washed, filtered and dried to obtain activated lignin; 20 parts of activated lignin, 10 parts of 3-aminopropyltrimethoxysilane, 80 parts of deionized water and 360 parts of anhydrous ethanol are mixed evenly, reacted at 55°C for 7 hours, filtered, washed and dried to obtain amino lignin;

[0058] Step (3): 20 parts of amino lignin and 180 parts of toluene were mixed evenly, 30 parts of modified mica powder were added, and the mixture was refluxed at 115°C for 16 hours to obtain an intermediate; 30 parts of the intermediate were mixed evenly with 18 parts of DOPO and 330 parts of anhydrous ethanol, and the mixture was reacted at 55°C for 11 hours to obtain a flame retardant;

[0059] The preparation method of composite graphene is as follows:

[0060] Step S1: ultrasonically dispersing 15 parts of graphene oxide in N,N-dimethylformamide to obtain a 9 mg / mL graphene dispersion, adding 75 parts of isophorone diisocyanate and 0.3 parts of dibutyltin diosilicate under nitrogen protection, reacting at 75°C for 7 hours, filtering, washing, and drying to obtain isocyanate-based graphene;

[0061] Step S2: ultrasonically dispersing 15 parts of isocyanate-based graphene in N,N-dimethylformamide to obtain a 6 mg / mL isocyanate-based graphene dispersion, adding 60 parts of resveratrol and 0.3 parts of dibutyltin disilicate under nitrogen protection, reacting at 75° C. for 7 hours, filtering, washing, and drying to obtain double-bond-containing graphene;

[0062] Step S3: Theobromine and 35 wt % sodium hydroxide solution were mixed to obtain a 9 mg / mL mixed solution; 15 parts of double-bond graphene were dispersed in 225 parts of N,N-dimethylformamide, 200 parts of the mixed solution were added and mixed evenly, and the mixture was reacted at 75° C. for 7 h. After filtering, washing, and drying, composite graphene was obtained.

[0063] Example 3: A method for preparing protective wear-resistant and long-life silicone rubber, comprising the following processes:

[0064] 105 parts of methyl vinyl silicone rubber, 50 parts of fumed silica and 5 parts of hydroxy silicone oil were mixed for 30 minutes, and a mixture of 50 parts of aluminum hydroxide, 40 parts of flame retardant, 20 parts of composite graphene and 8 parts of silane coupling agent was added and mixed for another 30 minutes. The mixture was subjected to high temperature treatment at 170°C for 4 hours, cooled to room temperature, and 2.2 parts of vulcanizing agent was added and mixed evenly to obtain a rubber mixture. The rubber mixture was subjected to a first stage vulcanization (carried out on a flat vulcanizing press at a temperature of 175°C, a molding pressure of 15 MPa, and a time of 20 minutes) and a second stage vulcanization (carried out in a blast drying oven at a temperature of 180°C and a time of 3 hours) to obtain silicone rubber.

[0065] The preparation method of the flame retardant is as follows:

[0066] Step (1): adjusting 1300 parts of 0.01 mol / L Tris-HCl buffer solution to pH=8.5, adding dopamine hydrochloride and mixing evenly to obtain a 5 g / L dopamine solution; adding 40 parts of mica powder to the dopamine solution and stirring for 24 hours, filtering, washing, and drying to obtain modified mica powder;

[0067] Step (2): 20 parts of alkali lignin, 15 parts of 37 wt% formaldehyde solution and 1.2 parts of sodium hydroxide are mixed evenly, reacted at 100°C for 3 hours, washed, filtered and dried to obtain activated lignin; 20 parts of activated lignin, 12 parts of 3-aminopropyltrimethoxysilane, 100 parts of deionized water and 400 parts of anhydrous ethanol are mixed evenly, reacted at 60°C for 8 hours, filtered, washed and dried to obtain amino lignin;

[0068] Step (3): 20 parts of amino lignin and 200 parts of toluene are mixed evenly, 40 parts of modified mica powder are added, and the mixture is refluxed at 120°C for 17 hours to obtain an intermediate; 40 parts of the intermediate, 32 parts of DOPO, and 480 parts of anhydrous ethanol are mixed evenly, and the mixture is reacted at 60°C for 12 hours to obtain a flame retardant;

[0069] The preparation method of composite graphene is as follows:

[0070] Step S1: ultrasonically dispersing 20 parts of graphene oxide in N,N-dimethylformamide to obtain a 10 mg / mL graphene dispersion, adding 120 parts of isophorone diisocyanate and 0.6 parts of dibutyltin diisocyanate under nitrogen protection, reacting at 80°C for 8 hours, filtering, washing, and drying to obtain isocyanate-based graphene;

[0071] Step S2: ultrasonically dispersing 20 parts of isocyanate-based graphene in N,N-dimethylformamide to obtain a 7 mg / mL isocyanate-based graphene dispersion, adding 100 parts of resveratrol and 0.6 parts of dibutyltin disilicate under nitrogen protection, reacting at 80° C. for 8 hours, filtering, washing, and drying to obtain double-bond-containing graphene;

[0072] Step S3: Theobromine and 40 wt % sodium hydroxide solution were mixed evenly to obtain a 10 mg / mL mixed solution; 20 parts of double-bond graphene were dispersed in 400 parts of N,N-dimethylformamide, 200 parts of the mixed solution were added and mixed evenly, and the mixture was reacted at 80° C. for 8 h. After filtering, washing, and drying, composite graphene was obtained.

[0073] Comparative Example 1: The silicone rubber includes the following components by weight: 95 parts of base rubber, 30 parts of fumed silica, 3 parts of hydroxy silicone oil, 30 parts of aluminum hydroxide, 10 parts of graphene oxide, 20 parts of flame retardant, 2 parts of silane coupling agent, and 0.6 parts of vulcanizing agent. In Comparative Example 1, the composite graphene is replaced with graphene oxide of the same mass. The other steps and processes are the same as those in Example 1.

[0074] Comparative Example 2: The silicone rubber includes the following components by weight: 95 parts of base rubber, 30 parts of fumed silica, 3 parts of hydroxy silicone oil, 50 parts of aluminum hydroxide, 10 parts of composite graphene, 2 parts of silane coupling agent, and 0.6 parts of vulcanizing agent. In Comparative Example 2, the flame retardant is replaced with aluminum hydroxide of the same mass. The other steps and processes are the same as those in Example 1.

[0075] Comparative Example 3: The silicone rubber includes the following components by weight: 95 parts of base rubber, 30 parts of fumed silica, 3 parts of hydroxy silicone oil, 30 parts of aluminum hydroxide, 5 parts of composite graphene, 20 parts of flame retardant, 2 parts of silane coupling agent, and 0.6 parts of vulcanizing agent. In Comparative Example 3, 5 parts of composite graphene are added, and the other steps and processes are the same as those in Example 1.

[0076] Comparative Example 4: A method for preparing protective wear-resistant and long-life silicone rubber, comprising the following processes:

[0077] Step S1: ultrasonically dispersing 15 parts of graphene oxide in N,N-dimethylformamide to obtain a 9 mg / mL graphene dispersion, adding 75 parts of isophorone diisocyanate and 0.3 parts of dibutyltin diosilicate under nitrogen protection, reacting at 75°C for 7 hours, filtering, washing, and drying to obtain isocyanate-based graphene;

[0078] Step S2: ultrasonically dispersing 15 parts of isocyanate-based graphene in N,N-dimethylformamide to obtain a 6 mg / mL isocyanate-based graphene dispersion, adding 90 parts of resveratrol and 0.3 parts of dibutyltin disilicate under nitrogen protection, reacting at 75° C. for 7 hours, filtering, washing, and drying to obtain double-bond-containing graphene;

[0079] Step S3: Theobromine and 35 wt % sodium hydroxide solution were mixed to obtain a 9 mg / mL mixed solution; 15 parts of double-bond graphene were dispersed in 225 parts of N,N-dimethylformamide, 200 parts of the mixed solution were added and mixed to obtain a composite graphene; the mixture was reacted at 75° C. for 7 h, and the composite graphene was obtained after filtering, washing, and drying.

[0080] Compared with Example 2, in step S2 of Comparative Example 4, the mass ratio of isocyanate graphene to resveratrol is 1:6; the other steps are the same as those in Example 2.

[0081] Experiment: The silicone rubber obtained in Examples 1-3 and Comparative Examples 1-4 was used to prepare samples, and their properties were tested and the test results were recorded:

[0082] Limiting oxygen index (LOI) was determined according to ASTM D2863, with specimen dimensions of 125 mm × 6.5 mm × 3 mm. Shore hardness was determined according to GB / T 531-2008. Tensile strength was determined according to GB / T 528-2009 at a rate of 500 mm / min. UV aging testing was conducted according to GB / T 16422-2014, using a xenon arc lamp at an irradiation intensity of 0.5 W / m 2 (340nm), after UV aging the silicone rubber for 5 days, the tensile strength before and after aging was measured, and the tensile strength retention rate was calculated.

[0083] Test results

[0084]

[0085] According to the data in the above table, we can clearly draw the following conclusions:

[0086] Compared with Examples 1-3, the LOI value, hardness, and tensile strength retention rate of the products obtained in Comparative Example 1 and Comparative Example 2 are all reduced, indicating that compared with graphene oxide, the composite graphene prepared by the present invention can improve the wear resistance and oxidation resistance of silicone rubber; at the same time, compared with aluminum hydroxide, the flame retardant prepared by the present invention has better flame retardant effect and can also improve the aging resistance of silicone rubber.

[0087] Compared with Examples 1-3, the hardness and tensile properties of the product obtained in Comparative Example 3 showed a decrease, which indicates that the performance of the silicone rubber prepared by the present invention is affected by its component ratio. By selecting the component ratio within the said range, a material with excellent mechanical properties can be prepared.

[0088] Compared with Examples 1-3, the tensile strength of the product obtained in Comparative Example 4 is decreased. It can be seen that increasing the amount of resveratrol added will lead to an increase in double bond sites and an increase in the degree of cross-linking, thereby resulting in a decrease in tensile strength.

[0089] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include," "comprise," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0090] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing protective wear-resistant and long-life silicone rubber, characterized by: The steps include: The base rubber, fumed silica and hydroxy silicone oil are mixed for 15-30 minutes, a mixture of aluminum hydroxide, flame retardant, composite graphene and silane coupling agent is added, and the mixing is continued for 15-30 minutes. The mixture is subjected to high temperature treatment at 160-170°C for 2-4 hours, cooled to room temperature, and a vulcanizing agent is added and mixed uniformly to obtain a rubber mixture; the rubber mixture is subjected to first-stage vulcanization and second-stage vulcanization in sequence to obtain silicone rubber; The silicone rubber comprises the following components by weight: 95-105 parts of base rubber, 30-50 parts of fumed silica, 3-5 parts of hydroxy silicone oil, 30-50 parts of aluminum hydroxide, 20-40 parts of flame retardant, 10-20 parts of composite graphene, 2-8 parts of silane coupling agent, and 0.6-2.2 parts of vulcanizing agent; The preparation method of the flame retardant is as follows: Step (1): adjusting the pH of the Tris-HCl buffer solution to 8.5, adding dopamine hydrochloride and mixing uniformly to obtain a dopamine solution; adding mica powder to the dopamine solution and stirring for 22-24 hours, filtering, washing, and drying to obtain modified mica powder; Step (2): uniformly mixing alkali lignin, formaldehyde solution and sodium hydroxide, reacting at 90-100° C. for 2-3 hours, washing, filtering and drying to obtain activated lignin; uniformly mixing activated lignin with 3-aminopropyltrimethoxysilane, deionized water and anhydrous ethanol, reacting at 50-60° C. for 6-8 hours, filtering, washing and drying to obtain amino lignin; Step (3): uniformly mixing amino lignin and toluene, adding modified mica powder, and reflux reaction at 110-120° C. for 15-17 hours to obtain an intermediate; uniformly mixing the intermediate with DOPO and anhydrous ethanol, and reacting at 50-60° C. for 10-12 hours to obtain a flame retardant; The preparation method of the composite graphene is as follows: Step S1: ultrasonically dispersing graphene oxide in N,N-dimethylformamide to obtain a graphene dispersion, adding isophorone diisocyanate and dibutyltin diisocyanate under nitrogen protection, reacting at 70-80° C. for 6-8 hours, filtering, washing, and drying to obtain isocyanate-based graphene; Step S2: ultrasonically dispersing the isocyanate-based graphene in N,N-dimethylformamide to obtain an isocyanate-based graphene dispersion, adding resveratrol and dibutyltin disilicate under nitrogen protection, reacting at 70-80° C. for 6-8 hours, filtering, washing, and drying to obtain double-bond-containing graphene; Step S3: mixing theobromine and sodium hydroxide solution to obtain a mixed solution; dispersing the double-bond graphene in N,N-dimethylformamide, adding the mixed solution to the mixture, mixing uniformly, reacting at 70-80° C. for 6-8 hours, filtering, washing, and drying to obtain composite graphene; In the step (3), the mass ratio of amino lignin to toluene and modified mica powder is 1:(8-10):(1-2).

2. The method for preparing a protective wear-resistant and long-life silicone rubber according to claim 1, characterized in that: The base rubber is methyl vinyl silicone rubber.

3. The method for preparing a protective wear-resistant and long-life silicone rubber according to claim 1, characterized in that: In the step S1, the mass ratio of graphene oxide, isophorone diisocyanate and dibutyltin dilaurate is 1:(4-6):(0.01-0.03).

4. The method for preparing a protective wear-resistant and long-life silicone rubber according to claim 1, characterized in that: The silane coupling agent is 3-glycidylpropyltrimethoxysilane.

5. The method for preparing a protective wear-resistant and long-life silicone rubber according to claim 1, characterized in that: The process conditions of the one-stage vulcanization are: carried out on a flat vulcanizing machine, a temperature of 160-175° C., a molding pressure of 10-15 MPa, and a time of 10-20 minutes.

6. A protective, wear-resistant, and long-life silicone rubber prepared according to the preparation method according to any one of claims 1 to 5.

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