Protective wear-resistant long-life silicone rubber and preparation method thereof

Abstract

The invention relates to the technical field of silicone rubber, in particular to protective wear-resistant long-life silicone rubber and a preparation method thereof. The silicone rubber comprises the following components in parts by weight: 95-105 parts of base rubber, 30-50 parts of fumed silica, 3-5 parts of hydroxyl silicone oil, 30-50 parts of aluminum hydroxide, 20-40 parts of a flame retardant, 10-20 parts of composite graphene, 2-8 parts of a silane coupling agent and 0.6-2.2 parts of a vulcanizing agent. The silicone rubber is prepared by taking raw methyl vinyl silicone rubber as a base material, taking fumed silica and composite graphene as reinforcing fillers, taking aluminum hydroxide and a flame retardant as flame-retardant fillers and taking hydroxyl silicone oil as a structural control agent and adding a silane coupling agent and a vulcanizing agent. The silicone rubber prepared by the invention has excellent flame retardant property, wear resistance and mechanical property, and also has aging resistance, so that the service life of the silicone rubber is prolonged.

Description

Technical Field

[0001] The 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 more and more important in various industries. Silicone rubber is a high-performance elastic material made of silicon raw materials and rubber. It has excellent high temperature resistance, low temperature resistance, corrosion resistance and insulation properties, and is widely used in electronics, automobiles, medical, aerospace and other fields. However, the wear resistance of traditional silicone rubber is not high, and it is easily subject to wear and scratches, resulting in a short life; silicone rubber is not elastic enough, and it is easy to crack and deform, affecting its service life and effect; the durability and stability in harsh environments such as high temperature, acid and alkali are poor, and it 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: A method for preparing protective wear-resistant and long-life silicone rubber comprises the following steps: 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 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.

[0006] 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.

[0007] Furthermore, the base rubber is methyl vinyl silicone rubber.

[0008] Furthermore, the preparation method of the flame retardant is as follows: Step (1): adjusting the pH value of the Tris-HCl buffer solution to 8.5, adding dopamine hydrochloride and mixing evenly 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 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; Step (3): Evenly mix the amino lignin and toluene, add the modified mica powder, and reflux for reaction at 110-120° C. for 15-17 hours to obtain an intermediate; evenly mix the intermediate, DOPO, and anhydrous ethanol, and react at 50-60° C. for 10-12 hours to obtain a flame retardant.

[0009] In the above technical scheme, firstly, 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 mica powder. The polar groups such as hydroxyl and amino groups on polydopamine produce covalent and non-covalent effects with 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 introducing flame retardant elements such as P, N, and Si into the lignin molecular chain through chemical modification, it can be made The flame retardant properties of the material are greatly improved. First, the lignin is treated with hydroxymethylation by a hydrothermal method to obtain activated lignin, and then the amino group is introduced through the hydrolysis of 3-aminopropyltrimethoxysilane to obtain amino lignin; the modified mica powder and the 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.

[0010] Furthermore, in step (1), the concentration of the Tris-HCl buffer 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.

[0011] 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).

[0012] 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).

[0013] Furthermore, in the step (3), the mass ratio of amino lignin to toluene and modified mica powder is 1:(8-10):(1-2).

[0014] Furthermore, in step (3), the mass ratio of the intermediate to DOPO and anhydrous ethanol is 1:(0.4-0.8):(10-12).

[0015] Furthermore, 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 graphene in N,N-dimethylformamide to obtain an isocyanate 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: 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 into the mixed solution and mixed evenly, reacted at 70-80° C. for 6-8 hours, filtered, washed and dried to obtain composite graphene.

[0016] In the above technical scheme, graphene oxide is modified by isophorone diisocyanate to introduce isocyanate groups; then resveratrol is grafted on the surface of isocyanate graphene to introduce double bonds; finally, an environmentally friendly and low-cost biomass compound theobromine is used as a nucleophilic reagent to reduce graphene oxide through a one-step "SN2 nucleophilic reaction" to successfully load theobromine on the surface of graphene containing double bonds to obtain composite graphene. Theobromine (TB) has excellent antioxidant, anti-radiation and free radical scavenging effects. It is a kind of green, environmentally friendly, resource-rich and widely available natural antioxidant, which 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 in methyl vinyl silicone rubber raw rubber, thereby improving the hardness of silicone rubber.

[0017] Furthermore, in step S1, the concentration of the graphene dispersion is 8-10 mg / mL.

[0018] Furthermore, in step S1, the mass ratio of graphene oxide, isophorone diisocyanate and dibutyltin dilaurate is 1:(4-6):(0.01-0.03).

[0019] Furthermore, in step S2, the concentration of the isocyanate graphene dispersion is 5-7 mg / mL.

[0020] Furthermore, in step S2, the mass ratio of isocyanate graphene, resveratrol and dibutyltin dilaurate is 1:(3-5):(0.01-0.03).

[0021] 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 %.

[0022] 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.

[0023] Furthermore, the silane coupling agent is 3-glycidylpropyltrimethoxysilane.

[0024] Furthermore, the vulcanizing agent is a dipentadienyl vulcanizing agent.

[0025] Furthermore, the mixing temperature is 90-100°C.

[0026] Furthermore, the process conditions of the one-stage vulcanization are: carried out on a flat vulcanizing machine, at a temperature of 160-175° C., a molding pressure of 10-15 MPa, and a time of 10-20 min.

[0027] Furthermore, the process conditions of the two-stage vulcanization are: carried out in a forced air drying oven, at a temperature of 170-180° C., and for 1-3 hours.

[0028] Compared with the prior art, the present invention has the following beneficial effects: 1. The protective wear-resistant and long-life silicone rubber and its preparation method of the present invention use dopamine to coat the surface of mica powder through self-polymerization advantage, which can provide better adhesion and help to combine with other functional components. Then, polydopamine and amino lignin undergo Schiff base reaction to obtain an intermediate containing C=N bond. The C=N bond of the intermediate reacts with the PH bond of DOPO to finally obtain a flame retardant containing P, N, and Si, which can make the silicone rubber have excellent flame retardant properties. Among them, mica powder has good wear resistance, toughness, insulation, high temperature resistance and other characteristics, which can enhance the wear resistance and durability of silicone rubber and improve its stability in harsh environments; at the same time, lignin is also an excellent free radical scavenger, and the aromatic ring in its molecule will be conjugated with active groups (such as methoxy, phenolic, carbonyl and vinyl), thereby giving lignin anti-ultraviolet radiation performance, which can improve the anti-aging property of silicone rubber and thus extend its service life.

[0029] 2. The present invention relates to 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 of the two, reducing agglomeration, and improving the heat resistance and wear resistance of silicone rubber. At the same time, the introduction of theobromine can improve the antioxidant properties of graphene oxide, thereby improving the aging resistance of silicone rubber.

[0030] 3. A protective wear-resistant and long-life silicone rubber and its preparation method of the present invention, with methyl vinyl silicone rubber raw rubber as the base material, fumed silica and composite graphene as reinforcing fillers to increase the strength and hardness of silicone rubber, aluminum hydroxide and flame retardant as flame retardant fillers, hydroxy silicone oil as a structuring control agent, silane coupling agent and vulcanizing agent are added to improve the overall performance of silicone rubber, and a heat-vulcanized silicone rubber is obtained, which has excellent flame retardant properties, wear resistance and mechanical strength, and is suitable for various protective wear-resistant and long-life application fields. Among them, the addition of flame retardant can replace part of the amount of aluminum hydroxide, and has better flame retardant effect and mechanical properties, thereby improving the flame retardant properties and mechanical strength of silicone rubber; fumed silica and composite graphene as reinforcing fillers can enhance the wear resistance and mechanical strength of silicone rubber and extend its service life. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] In this embodiment, the silane coupling agent is 3-glycidylpropyltrimethoxysilane; the vulcanizing agent is dipentadienyl vulcanizing agent; the methyl vinyl silicone rubber raw rubber: model 110-2, average molar mass 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: terminal hydroxyl polydimethylsiloxane, model JP-107, sourced from Shenzhen Jipeng Silicon Fluoride Materials Co., Ltd.; aluminum hydroxide: average particle size 1-10μm, 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 1-3nm, diameter 4-7μm, number of layers 2-5, sourced from Zhejiang Zhiti Nano Micro New Materials Co., Ltd.

[0033] In the following examples and comparative examples, 1 part is equal to 10 g.

[0034] Embodiment 1: A method for preparing a protective wear-resistant and long-life silicone rubber, comprising the following processes: 95 parts of methyl vinyl silicone rubber, 30 parts of fumed silica and 3 parts of hydroxy silicone oil were mixed for 15 minutes, 30 parts of aluminum hydroxide, 20 parts of flame retardant, 10 parts of composite graphene and 2 parts of silane coupling agent were added, and the mixture was further mixed for 15 minutes, and the mixture was treated at a high temperature of 160°C for 2 hours, cooled to room temperature, and 0.6 parts of vulcanizing agent were added and mixed evenly to obtain a mixed rubber; the mixed rubber was successively subjected to a first-stage vulcanization (carried out on a flat vulcanizer, at a temperature of 160°C, a molding pressure of 10Mpa, 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) to obtain silicone rubber; The preparation method of the flame retardant is as follows: 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; 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; Step (3): 20 parts of amino lignin and 160 parts of toluene are mixed evenly, 20 parts of modified mica powder are added, and the mixture is refluxed at 110° C. for 15 hours to obtain an intermediate; 20 parts of the intermediate, 8 parts of DOPO and 200 parts of anhydrous ethanol are mixed evenly, and the mixture is reacted at 50° C. for 10 hours to obtain a flame retardant; The preparation method of composite graphene is as follows: Step S1: ultrasonically disperse 10 parts of graphene oxide in N,N-dimethylformamide to obtain 8 mg / mL graphene dispersion, add 40 parts of isophorone diisocyanate and 0.1 parts of dibutyltin disilicate under nitrogen protection, react at 70° C. for 6 hours, filter, wash and dry to obtain isocyanate graphene; Step S2: ultrasonically dispersing 10 parts of isocyanate graphene in N,N-dimethylformamide to obtain a 5 mg / mL isocyanate 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; Step S3: Theobromine and 30 wt % sodium hydroxide solution are mixed evenly to obtain an 8 mg / mL mixed solution; 10 parts of double bond-containing graphene are dispersed in 100 parts of N, N-dimethylformamide, 200 parts of the mixed solution are added and mixed evenly, and the mixture is reacted at 70° C. for 6 hours, and composite graphene is obtained after filtering, washing and drying.

[0035] Embodiment 2: A method for preparing a protective wear-resistant and long-life silicone rubber, comprising the following processes: 100 parts of methyl vinyl silicone rubber, 40 parts of fumed silica and 4 parts of hydroxy silicone oil were mixed for 20 minutes, 40 parts of aluminum hydroxide, 30 parts of flame retardant, 15 parts of composite graphene and 6 parts of silane coupling agent were added, and the mixture was further mixed for 20 minutes, and the mixture was treated at a high temperature of 165°C for 3 hours, cooled to room temperature, and 1 part of vulcanizing agent was added and mixed evenly to obtain a mixed rubber; the mixed rubber was successively subjected to a first-stage vulcanization (carried out on a flat vulcanizer, at a temperature of 170°C, a molding pressure of 12Mpa, and a time of 15 minutes) and a second-stage vulcanization (carried out in a blast drying oven, at a temperature of 175°C and a time of 2 hours) to obtain silicone rubber; The preparation method of the flame retardant is as follows: 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; 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; Step (3): 20 parts of amino lignin and 180 parts of toluene are mixed evenly, 30 parts of modified mica powder are added, and the mixture is refluxed at 115° C. for 16 hours to obtain an intermediate; 30 parts of the intermediate, 18 parts of DOPO and 330 parts of anhydrous ethanol are mixed evenly, and the mixture is reacted at 55° C. for 11 hours to obtain a flame retardant; The preparation method of composite graphene is as follows: Step S1: ultrasonically disperse 15 parts of graphene oxide in N,N-dimethylformamide to obtain a 9 mg / mL graphene dispersion, add 75 parts of isophorone diisocyanate and 0.3 parts of dibutyltin disilicate under nitrogen protection, react at 75° C. for 7 hours, and obtain isocyanate-based graphene after filtering, washing and drying; Step S2: ultrasonically dispersing 15 parts of isocyanate graphene in N,N-dimethylformamide to obtain a 6 mg / mL isocyanate 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; Step S3: Theobromine and 35 wt % sodium hydroxide solution are mixed evenly to obtain a 9 mg / mL mixed solution; 15 parts of double bond-containing graphene are dispersed in 225 parts of N, N-dimethylformamide, 200 parts of the mixed solution are added and mixed evenly, and the mixture is reacted at 75° C. for 7 hours, and composite graphene is obtained after filtering, washing and drying.

[0036] Embodiment 3: A method for preparing a protective wear-resistant and long-life silicone rubber, comprising the following processes: 105 parts of methyl vinyl silicone rubber, 50 parts of fumed silica and 5 parts of hydroxy silicone oil were mixed for 30 minutes, 50 parts of aluminum hydroxide, 40 parts of flame retardant, 20 parts of composite graphene and 8 parts of silane coupling agent were added, and the mixture was further mixed for 30 minutes, and the mixture was treated at a high temperature of 170°C for 4 hours, cooled to room temperature, and 2.2 parts of vulcanizing agent were added and mixed evenly to obtain a mixed rubber; the mixed rubber was successively subjected to a first-stage vulcanization (carried out on a flat vulcanizer, at a temperature of 175°C, a molding pressure of 15Mpa, 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; The preparation method of the flame retardant is as follows: 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; 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; 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; The preparation method of composite graphene is as follows: 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 disilicate under nitrogen protection, reacting at 80° C. for 8 hours, filtering, washing, and drying to obtain isocyanate-based graphene; Step S2: ultrasonically dispersing 20 parts of isocyanate graphene in N,N-dimethylformamide to obtain a 7 mg / mL isocyanate 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; Step S3: Theobromine and 40 wt % sodium hydroxide solution are mixed evenly to obtain a 10 mg / mL mixed solution; 20 parts of double bond-containing graphene are dispersed in 400 parts of N, N-dimethylformamide, 200 parts of the mixed solution are added and mixed evenly, and the mixture is reacted at 80° C. for 8 hours, and composite graphene is obtained after filtering, washing and drying.

[0037] 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, and the other steps and processes are the same as those in Example 1.

[0038] 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, and the other steps and processes are the same as in Example 1.

[0039] 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.

[0040] Comparative Example 4: A method for preparing a protective wear-resistant and long-life silicone rubber, comprising the following processes: Step S1: ultrasonically disperse 15 parts of graphene oxide in N,N-dimethylformamide to obtain a 9 mg / mL graphene dispersion, add 75 parts of isophorone diisocyanate and 0.3 parts of dibutyltin disilicate under nitrogen protection, react at 75° C. for 7 hours, and obtain isocyanate-based graphene after filtering, washing and drying; Step S2: ultrasonically dispersing 15 parts of isocyanate graphene in N,N-dimethylformamide to obtain a 6 mg / mL isocyanate 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; Step S3: theobromine and 35wt% sodium hydroxide solution are mixed evenly to obtain a 9mg / mL mixed solution; 15 parts of double bond-containing graphene are dispersed in 225 parts of N,N-dimethylformamide, 200 parts of the mixed solution are added and mixed evenly, reacted at 75°C for 7h, filtered, washed and dried to obtain composite graphene; 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.

[0041] Experiment: The silicone rubber obtained in Examples 1-3 and Comparative Examples 1-4 was taken to prepare samples, and the properties thereof were tested and the test results were recorded: The limiting oxygen index (LOI value) was determined according to ASTM D2863: the sample size was 125 mm × 6.5 mm × 3 mm; the Shore hardness was determined according to GB / T 531-2008; the tensile strength was determined according to GB / T 528-2009, with a tensile rate of 500 mm / min; the UV aging test was conducted according to GB / T16422-2014, with a xenon arc lamp as the light source and 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.

[0042] Test Results

[0043] According to the data in the above table, we can clearly draw the following conclusions: Compared with Examples 1-3, the LOI value, hardness, and tensile strength retention rate of the products obtained in Comparative Examples 1 and 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.

[0044] Compared with Examples 1-3, the hardness and tensile properties of the product obtained in Comparative Example 3 both show 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.

[0045] 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.

[0046] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process method article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process method article or device.

[0047] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is 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 can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a protective wear-resistant and long-life silicone rubber, characterized in that: 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, and the mixture is treated at a high temperature of 160-170°C for 2-4 hours, cooled to room temperature, and a vulcanizing agent is added and mixed evenly to obtain a mixed rubber; the mixed rubber is sequentially subjected to a first-stage vulcanization and a second-stage vulcanization 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 value of the Tris-HCl buffer solution to 8.5, adding dopamine hydrochloride and mixing evenly 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 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; Step (3): Evenly mix the amino lignin and toluene, add the modified mica powder, and reflux for reaction at 110-120° C. for 15-17 hours to obtain an intermediate; evenly mix the intermediate, DOPO, and anhydrous ethanol, and react at 50-60° C. for 10-12 hours to obtain a flame retardant.

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

4. The method for preparing a protective wear-resistant and long-life silicone rubber according to claim 1, characterized in that: 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 graphene in N,N-dimethylformamide to obtain an isocyanate 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: 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 into the mixed solution and mixed evenly, reacted at 70-80° C. for 6-8 hours, filtered, washed and dried to obtain composite graphene.

5. The method for preparing a protective wear-resistant and long-life silicone rubber according to claim 4, 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).

6. 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.

7. 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, at a temperature of 160-175° C., a molding pressure of 10-15 MPa, and a time of 10-20 min.

8. A protective, wear-resistant and long-life silicone rubber prepared according to the preparation method according to any one of claims 1 to 7.

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