Flame-retardant rubber and method for producing the same

Abstract

The application relates to the field of rubber materials, in particular to a flame-retardant rubber and a preparation method thereof, which comprises the following components in parts by weight: natural rubber 50-70 parts, solution polymerized styrene-butadiene rubber 25-35 parts, liquid phenyl silicone rubber 10-20 parts, white carbon black 30-40 parts, silane coupling agent Si-69 0.5-1.5 parts, stearic acid 1-3 parts, composite filler 30-50 parts, flame retardant 5-10 parts, polysiloxane grafted graphene 3-5 parts, antioxidant 0.5-1 part, sulfur 1-2 parts and accelerator 0.5-1 part. The prepared flame-retardant rubber has good mechanical properties and flame-retardant properties. The prepared flame-retardant rubber has low inherent frequency and creep as a raw material of a vibration isolator, and has good vibration isolation effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of rubber materials, in particular to a flame-retardant rubber and a preparation method thereof. BACKGROUND

[0002] Noise and vibration are important indicators affecting the underwater stealth performance of a ship. A 10 decibel reduction in radiated noise can reduce the effective distance of a passive sonar by half and increase the effective distance of a self sonar by nearly one time, thereby greatly improving the detection performance of the ship. A vibration isolator is usually used in the ship body to improve noise and vibration. This technology has been applied to various water surface and underwater devices, greatly improving the stealth performance of various equipment. However, with increasing safety requirements, the non-metallic rubber material on the vibration isolator is required to have strict flame-retardant requirements. At present, the method for improving the flame-retardant performance of the rubber on the vibration isolator is mainly to add flame-retardant fillers to the rubber body. However, the direct addition of flame-retardant fillers greatly affects the mechanical properties of the rubber body, and further affects the vibration reduction effect.

[0003] Therefore, there is an urgent need for a rubber material for a vibration isolator that can meet the original high structural strength requirement and has outstanding flame-retardant performance. SUMMARY

[0004] The present application aims to solve the above technical problems and provides a flame-retardant rubber and a preparation method thereof.

[0005] The technical scheme adopted is as follows:

[0006] A flame-retardant rubber, including the following components in parts by weight:

[0007] 50-70 parts of natural rubber, 25-35 parts of solution-polymerized styrene-butadiene rubber, 10-20 parts of liquid phenyl silicone rubber, 30-40 parts of white carbon black, 0.5-1.5 parts of silane coupling agent Si-69, 1-3 parts of stearic acid, 30-50 parts of composite filler, 5-10 parts of flame retardant, 3-5 parts of polysiloxane grafted graphene, 0.5-1 part of antioxidant, 1-2 parts of sulfur, and 0.5-1 part of accelerator.

[0008] Further, the liquid phenyl silicone rubber has a phenyl content of 10-20% and a viscosity of 3000-20000 mPa·s.

[0009] Further, the flame retardant is a DOPO-carbon nanotube composite.

[0010] Further, the preparation method of the DOPO-carbon nanotube composite is as follows:

[0011] The intermediate is prepared by heating DOPO to 130-140 DEG C, adding 1,4-butene diol after the DOPO is melted, and then stirring for 10-15 hours, adding toluene, stirring for 0.5-1 hour, adding methanol, and continuing to stir for 0.5-1 hour, and then filtering and drying the obtained product in vacuum to constant weight to obtain the intermediate;

[0012] The carbon nanotubes are added into a mixed acid composed of sulfuric acid and concentrated nitric acid, ultrasonic oscillation is carried out at room temperature for 30-60 minutes, stirring is carried out at 70-85 DEG C for 4-8 hours, water is added for dilution, and then filtering, washing until neutral, and drying in vacuum to obtain carboxylated carbon nanotubes, the carbon nanotubes are added into dichlorosulfoxide, ultrasonic oscillation is carried out for 15-30 minutes, DMF is added, stirring is carried out at 65-75 DEG C for 36-48 hours, residual dichlorosulfoxide is removed by distillation under reduced pressure, and then the obtained product is washed with THF and dried in vacuum to obtain acyl chloride carbon nanotubes.

[0013] The intermediate, acyl chloride carbon nanotubes and DMAC are mixed, ultrasonic oscillation is carried out for 15-30 minutes, pyridine is added dropwise, heating reflux is carried out for 36-48 hours, and then filtering, washing the obtained product with DMAC, and drying in vacuum to constant weight.

[0014] Further, the composite filler includes aluminum hydroxide, magnesium hydroxide, zinc borate and zinc hydroxystannate.

[0015] Further, the mass ratio of the aluminum hydroxide, magnesium hydroxide, zinc borate and zinc hydroxystannate is 20-30:20-30:1-5:1-5.

[0016] Further, the antioxidant includes antioxidant RD and antioxidant 4020, and the mass ratio of the antioxidant RD and antioxidant 4020 is 1-3:1-3.

[0017] The accelerator is accelerator NOBS and accelerator DTDM, and the mass ratio of the accelerator NOBS and accelerator DTDM is 3-5:1.

[0018] Further, the preparation method of the polysiloxane grafted graphene is as follows:

[0019] In a protective gas atmosphere, carboxylated graphene is added into toluene, ultrasonic dispersion is carried out, hydroxyl-terminated polysiloxane and p-toluene sulfonic acid are added, mixing is carried out uniformly, reaction is carried out at 100-120 DEG C for 8-12 hours, the reaction is completed, and then filtering, washing with toluene, and drying in vacuum to obtain the product.

[0020] Further, the mass ratio of the carboxylated graphene, hydroxyl-terminated polysiloxane and p-toluene sulfonic acid is 15-20:24-50:1.

[0021] The application further provides a preparation method of the flame-retardant rubber.

[0022] The natural rubber is baked at 40-60 DEG C for 3-5 hours, and after thin passing 10-15 times, mixing with solution styrene-butadiene rubber and liquid phenyl silicone rubber, the initial temperature of the internal mixer is 70-80 DEG C, after 3-5 minutes, adding white carbon black, silane coupling agent Si-69, stearic acid and antioxidant, after 1-2 minutes, adding polysiloxane grafted graphene, composite filler and flame retardant, mixing at 120-140 DEG C for 5-8 minutes, then discharging, adding sulfur and accelerator on the open mill, after thin passing 6-10 times, discharging, and after 24 hours, vulcanizing.

[0023] The beneficial effects of the present application are:

[0024] The present application provides a kind of flame-retardant rubber, natural rubber is widely used in shock-absorbing rubber with its excellent comprehensive performance, solution styrene-butadiene rubber can improve the aging resistance and the stability of dynamic and static stiffness ratio in compression vibration process of natural rubber, the introduction of benzene ring structure can improve the mechanical properties of flame-retardant rubber, liquid phenyl silicone rubber as damping additive, can effectively improve the damping performance of flame-retardant rubber, DOPO-carbon nanotube composite as DOPO derivative flame retardant containing P and N elements simultaneously, with gas phase and condensed phase flame-retardant effect, can improve the anti-dripping capacity of flame-retardant rubber when burning, promote matrix carbonization, play the role of barrier protection, polysiloxane grafted graphene can improve the agglomeration problem of graphene, effectively enhance the mechanical properties of flame-retardant rubber, the flame-retardant rubber prepared by the present application has good mechanical properties and flame-retardant performance, the flame-retardant rubber prepared by the present application as a vibration isolator raw material has low inherent frequency and creep, and good vibration isolation effect. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is the SEM graph of the flame-retardant rubber prepared in example 1 of the present application.

[0026] Figure 2 It is the damping performance comparison graph of example 1 and comparative examples 1 and 2 of the present application. DETAILED DESCRIPTION

[0027] Unless otherwise specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are used. Unless otherwise specified, the reagents or instruments used are conventional products that can be purchased on the market. The techniques not mentioned in the present application are referred to the prior art.

[0028] Example 1:

[0029] A kind of flame-retardant rubber, including the following component ingredients by weight fraction:

[0030] Natural rubber 65 parts, solution styrene-butadiene rubber 30 parts, liquid phenyl silicone rubber 12 parts, white carbon black 35 parts, silane coupling agent Si-69 1 part, stearic acid 2 parts, aluminum hydroxide 20 parts, magnesium hydroxide 20 parts, zinc borate 5 parts, zinc hydroxystannate 5 parts, flame retardant 8 parts, polysiloxane grafted graphene 5 parts, antioxidant RD 0.5 parts, antioxidant 4020 0.5 parts, sulfur 1 part, accelerator NOBS 0.6 parts, accelerator DTDM 0.2 parts.

[0031] The liquid phenyl silicone rubber has a phenyl content of 18% and a viscosity of 18800 mPa·s, and is purchased from Chengdu Senfa Rubber and Plastic Co., Ltd.

[0032] The flame retardant is a DOPO-carbon nanotube composite, and the preparation method is as follows:

[0033] 216g of DOPO is heated to 135℃, and after it is melted, 100g of 1,4-butenediol is added and reacted for 15h, then 300mL of toluene is added at 50℃, stirred for 0.5h, then 3L of methanol is added, and stirred for another 0.5h, filtered, and the obtained product is vacuum dried at 50℃ to constant weight to obtain an intermediate. 50g of carbon nanotubes is added to a mixed acid composed of sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, ultrasonic oscillation is performed at room temperature for 50min, then stirring is performed at 85℃ for 6h, after dilution with 5 times the volume of water, filtration is performed, washing is performed until neutral, and vacuum drying is performed to obtain carboxylated carbon nanotubes. The carbon nanotubes are added to 1L of dichlorosulfoxide, ultrasonic oscillation is performed for 30min, then DMF is added, stirring is performed at 70℃ for 48h, after removing the remaining dichlorosulfoxide by reduced pressure distillation, the obtained product is washed with THF, and vacuum dried at 50℃ to obtain acyl chloride carbon nanotubes. 100g of the intermediate, 15g of acyl chloride carbon nanotubes, and DMAC are mixed, ultrasonic oscillation is performed for 30min, then 10mL of pyridine is added dropwise, heating reflux reaction is performed for 48h, the obtained product is washed with DMAC, and vacuum dried at 50℃ to constant weight.

[0034] The preparation method of the polysiloxane grafted graphene is as follows:

[0035] In a protective gas atmosphere, carboxylated graphene is added to toluene, ultrasonic dispersion is performed, then hydroxyl-terminated polysiloxane and p-toluenesulfonic acid are added, the mass ratio of carboxylated graphene, hydroxyl-terminated polysiloxane, and p-toluenesulfonic acid is 20:25:1, uniform mixing is performed, then 120℃ reaction is performed for 12h, after the reaction is completed, room temperature is restored, filtration is performed, toluene washing is performed, and vacuum drying is performed to obtain the product.

[0036] The preparation method of the above-mentioned flame-retardant rubber is as follows:

[0037] The natural rubber is baked at 50℃ for 4h, and then mixed with solution styrene-butadiene rubber and liquid phenyl silicone rubber after 12 times of thin pass. The initial temperature of the internal mixer is 80℃, and then 300g of white carbon black, 1.5g of silane coupling agent Si-69, 3g of stearic acid, 0.5g of antioxidant RD, 0.5g of antioxidant 4020, 5g of polysiloxane grafted graphene, 20g of aluminum hydroxide, 20g of magnesium hydroxide, 5g of zinc borate, 5g of zinc hydroxystannate and 10g of flame retardant DOPO-carbon nanotube composite are added after 5min. The rubber is discharged after mixing at 140℃ for 6min, and then added with 2g of sulfur, 0.6g of accelerator NOBS and 0.2g of accelerator DTDM on an open mill. The rubber is discharged after 10 times of thin pass, and then vulcanized after 24h of storage at 150℃ and 10MPa.

[0038] Example 2

[0039] A flame-retardant rubber, comprising the following components in parts by weight:

[0040] The natural rubber is baked at 50℃ for 4h, and then mixed with solution styrene-butadiene rubber and liquid phenyl silicone rubber after 12 times of thin pass. The initial temperature of the internal mixer is 80℃, and then 300g of white carbon black, 1.5g of silane coupling agent Si-69, 3g of stearic acid, 0.5g of antioxidant RD, 0.5g of antioxidant 4020, 5g of polysiloxane grafted graphene, 20g of aluminum hydroxide, 20g of magnesium hydroxide, 5g of zinc borate, 5g of zinc hydroxystannate and 10g of flame retardant DOPO-carbon nanotube composite are added after 5min. The rubber is discharged after mixing at 140℃ for 6min, and then added with 2g of sulfur, 0.6g of accelerator NOBS and 0.2g of accelerator DTDM on an open mill. The rubber is discharged after 10 times of thin pass, and then vulcanized after 24h of storage at 150℃ and 10MPa.

[0041] The liquid phenyl silicone rubber has a phenyl content of 18% and a viscosity of 18800mPa·s, and is purchased from Chengdu Senfa Rubber and Plastic Co., Ltd.

[0042] The flame retardant is a DOPO-carbon nanotube composite, and the preparation method is as follows:

[0043] 216g of DOPO is heated to 140℃, and then 100g of 1,4-butenediol is added after it is melted. After 15h of reaction, 300mL of toluene is added after the temperature is reduced to 50℃, and then stirred for 1h. Then, 3L of methanol is added, and stirred for another 1h. The obtained product is vacuum dried at 50℃ to constant weight to obtain an intermediate. 50g of carbon nanotubes is added into a mixed acid composed of sulfuric acid and concentrated nitric acid with a volume ratio of 3:1, and ultrasonic oscillation is performed at room temperature for 60min. Then, stirring is performed at 85℃ for 8h. After dilution with 5 times the volume of water, filtration is performed, and then washed to neutral. After vacuum drying, carboxylated carbon nanotubes are obtained. The carbon nanotubes are added into 1L of dichlorosulfoxide, and ultrasonic oscillation is performed for 30min. Then, DMF is added, and stirring is performed at 75℃ for 48h. After removing the remaining dichlorosulfoxide by reduced pressure distillation, the obtained product is washed with THF, and vacuum dried at 50℃ to obtain acyl chloride carbon nanotubes. 100g of the intermediate, 15g of acyl chloride carbon nanotubes and DMAC are mixed, and ultrasonic oscillation is performed for 30min. Then, 10mL of pyridine is added dropwise, and heated to reflux for 48h. After filtration, the obtained product is washed with DMAC, and vacuum dried at 50℃ to constant weight.

[0044] The preparation method of the polysiloxane grafted graphene is as follows:

[0045] Carboxylated graphene is added into toluene in a protective gas atmosphere, ultrasonic dispersion is performed, hydroxyl-terminated polysiloxane and p-toluenesulfonic acid are added, the mass ratio of the carboxylated graphene, the hydroxyl-terminated polysiloxane and the p-toluenesulfonic acid is 20:50:1, uniform mixing is performed, reaction is performed at 120℃ for 12h, after the reaction is completed, vacuum drying is performed after room temperature recovery, toluene washing and extraction are performed.

[0046] The preparation method of the flame-retardant rubber is as follows:

[0047] The natural rubber is baked at 60℃ for 5h, thin pass is performed 15 times, and then mixing is performed with the solution styrene-butadiene rubber, the liquid phenyl silicone rubber, the white carbon black, the silane coupling agent Si-69, the stearic acid, the antioxidant RD, the antioxidant 4020, the polysiloxane grafted graphene, the aluminum hydroxide, the magnesium hydroxide, the zinc borate, the zinc hydroxystannate and the flame retardant DOPO-carbon nanotube composite, the initial temperature of the internal mixer is 80℃, the flame retardant is added after 2min, mixing is performed at 140℃ for 8min, and then the sulfur, the accelerator NOBS and the accelerator DTDM are added, thin pass is performed 10 times, and then the sheet is discharged, 24h is parked after vulcanization, the vulcanization temperature is 150℃, and the pressure is 10MPa.

[0048] Example 3:

[0049] A kind of flame-retardant rubber, including the following component ingredients by weight fraction:

[0050] The natural rubber is baked at 60℃ for 5h, thin pass is performed 15 times, and then mixing is performed with the solution styrene-butadiene rubber, the liquid phenyl silicone rubber, the white carbon black, the silane coupling agent Si-69, the stearic acid, the antioxidant RD, the antioxidant 4020, the polysiloxane grafted graphene, the aluminum hydroxide, the magnesium hydroxide, the zinc borate, the zinc hydroxystannate and the flame retardant DOPO-carbon nanotube composite, the initial temperature of the internal mixer is 80℃, the flame retardant is added after 2min, mixing is performed at 140℃ for 8min, and then the sulfur, the accelerator NOBS and the accelerator DTDM are added, thin pass is performed 10 times, and then the sheet is discharged, 24h is parked after vulcanization, the vulcanization temperature is 150℃, and the pressure is 10MPa.

[0051] The liquid phenyl silicone rubber is purchased from Chengdu Senfa Rubber and Plastic Co., Ltd., the phenyl content of the liquid phenyl silicone rubber is 18%, and the viscosity of the liquid phenyl silicone rubber is 18800mPa·s;

[0052] The flame retardant is a DOPO-carbon nanotube composite, and the preparation method is as follows:

[0053] The 216 g DOPO was heated to 130°C, and after it was melted, 100 g of 1,4-butene diol was added and reacted for 10 h. Then, 300 mL of toluene was added at 50°C, and stirred for 0.5 h. Then, 3 L of methanol was added, and stirred for another 0.5 h. Then, the product was extracted by filtration, and dried at 50°C under vacuum to constant weight to obtain an intermediate. Then, 50 g of carbon nanotubes was added into a mixed acid composed of sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, and ultrasonically oscillated at room temperature for 30 min. Then, it was stirred at 70°C for 4 h. After dilution with 5 times the volume of water, it was filtered, washed to neutral, and dried under vacuum to obtain carboxylated carbon nanotubes. Then, the carbon nanotubes were added into 1 L of dichlorosulfoxide, and ultrasonically oscillated for 15 min. Then, DMF was added, and stirred at 65°C for 36 h. After removing the residual dichlorosulfoxide by distillation under reduced pressure, the product was washed with THF, and dried at 50°C under vacuum to obtain acyl chloride carbon nanotubes. Then, 100 g of the intermediate, 15 g of acyl chloride carbon nanotubes, and DMAC were mixed, and ultrasonically oscillated for 15 min. Then, 10 mL of pyridine was added dropwise, and heated to reflux for 36 h. After filtration, the product was washed with DMAC, and dried at 50°C under vacuum to constant weight.

[0054] The preparation method of the polysiloxane grafted graphene is as follows:

[0055] In a protective gas atmosphere, carboxylated graphene was added into toluene, and ultrasonically dispersed. Then, hydroxyl-terminated polysiloxane and p-toluenesulfonic acid were added, and the mass ratio of carboxylated graphene, hydroxyl-terminated polysiloxane, and p-toluenesulfonic acid was 15:24:1. After mixing uniformly, it was reacted at 100°C for 8 h. After the reaction was completed, it was extracted by filtration, washed with toluene, and dried under vacuum to obtain the product.

[0056] The preparation method of the above flame-retardant rubber is as follows:

[0057] The natural rubber was baked at 40°C for 3 h, and thin passed 10 times. Then, it was mixed with solution styrene-butadiene rubber, liquid phenyl silicone rubber, and the following ingredients: white carbon black, silane coupling agent Si-69, stearic acid, antioxidant RD, antioxidant 4020, polysiloxane grafted graphene, aluminum hydroxide, magnesium hydroxide, zinc borate, zinc hydroxystannate, and flame retardant DOPO-carbon nanotube composite. After mixing in a mixer at an initial temperature of 70°C for 3 min, the following ingredients were added: sulfur, accelerator NOBS, and accelerator DTDM. After thin passing 6 times, the product was discharged, and placed on an open mill. After standing for 24 h, it was vulcanized at a temperature of 150°C and a pressure of 10 MPa.

[0058] Example 4:

[0059] A flame-retardant rubber, including the following components in parts by weight:

[0060] Natural rubber 70 parts, solution styrene-butadiene rubber 25 parts, liquid phenyl silicone rubber 20 parts, white carbon black 30 parts, silane coupling agent Si-69 1.5 parts, stearic acid 1 part, aluminum hydroxide 20 parts, magnesium hydroxide 20 parts, zinc borate 5 parts, zinc hydroxystannate 5 parts, flame retardant 10 parts, polysiloxane grafted graphene 3 parts, antioxidant RD 0.5 parts, antioxidant 4020 0.5 parts, sulfur 2 parts, accelerator NOBS 0.6 parts, accelerator DTDM 0.2 parts.

[0061] The preparation method of the flame retardant and the polysiloxane grafted graphene is the same as that in Example 1;

[0062] The preparation method of the above flame-retardant rubber is as follows:

[0063] The natural rubber is baked at 40℃ for 5h, and after thin passing 10 times, it is mixed with solution styrene-butadiene rubber and liquid phenyl silicone rubber. The initial temperature of the internal mixer is 80℃, and after 3min, white carbon black, silane coupling agent Si-69, stearic acid, antioxidant RD and antioxidant 4020 are added. After 2min, polysiloxane grafted graphene, aluminum hydroxide, magnesium hydroxide, zinc borate, zinc hydroxystannate and flame retardant DOPO-carbon nanotube composite are added, and after mixing at 120℃ for 8min, the rubber is discharged. Sulfur, accelerator NOBS and accelerator DTDM are added on the open mill, and after thin passing 6 times, the rubber is discharged. After standing for 24h, it is vulcanized at a temperature of 150℃ and a pressure of 10MPa.

[0064] Example 5:

[0065] A kind of flame-retardant rubber, including the following component ingredients by weight fraction:

[0066] Natural rubber 50 parts, solution styrene-butadiene rubber 35 parts, liquid phenyl silicone rubber 10 parts, white carbon black 40 parts, silane coupling agent Si-69 0.5 parts, stearic acid 3 parts, aluminum hydroxide 20 parts, magnesium hydroxide 20 parts, zinc borate 5 parts, zinc hydroxystannate 5 parts, flame retardant 5 parts, polysiloxane grafted graphene 5 parts, antioxidant RD 0.5 parts, antioxidant 4020 0.5 parts, sulfur 1 part, accelerator NOBS 0.6 parts, accelerator DTDM 0.2 parts.

[0067] The preparation method of the flame retardant and the polysiloxane grafted graphene is the same as that in Example 1;

[0068] The preparation method of the above flame-retardant rubber is as follows:

[0069] The natural rubber is baked at 60℃ for 3h, and after thin passing 15 times, mixing with solution styrene-butadiene rubber and liquid phenyl silicone rubber, the initial temperature of the internal mixer is 70℃, after 5min, adding white carbon black, silane coupling agent Si-69, stearic acid, antioxidant RD, antioxidant 4020, after 1min, adding polysiloxane grafted graphene, aluminum hydroxide, magnesium hydroxide, zinc borate, zinc hydroxystannate and flame retardant DOPO-carbon nanotube composite, after mixing at 140℃ for 5min, discharging, putting on the open mill, adding sulfur, accelerator NOBS and accelerator DTDM, after thin passing 10 times, discharging, after standing for 24h, vulcanizing, the vulcanizing temperature is 150℃, and the pressure is 10MPa.

[0070] Comparative Example 1:

[0071] The same as Example 1 basically, except that solution styrene-butadiene rubber is not added.

[0072] Comparative Example 2:

[0073] The same as Example 1 basically, except that liquid phenyl silicone rubber is not added.

[0074] Comparative Example 3:

[0075] The same as Example 1 basically, except that flame retardant DOPO-carbon nanotube composite is not added.

[0076] Comparative Example 4:

[0077] The same as Example 1 basically, except that DOPO and carbon nanotube are used to replace DOPO-carbon nanotube composite.

[0078] Comparative Example 5:

[0079] The same as Example 1 basically, except that polysiloxane grafted graphene is not added.

[0080] Comparative Example 6:

[0081] The same as Example 1 basically, except that graphene is used to replace polysiloxane grafted graphene.

[0082] Performance test:

[0083] The flame-retardant rubber prepared in Example 1-5 and Comparative Example 1-6 of the application is used as a sample for performance test;

[0084] The tensile strength, elongation at break and 100% and 300% modulus of the sample are determined according to GB / T528-2009.

[0085] The tear strength is determined according to GB / T529-2008.

[0086] The limiting oxygen index test uses a 5801A oxygen index tester produced by the VOUCH company, uses propane ignition, and adopts the standard GB-T 10707-2008.

[0087] The test results are shown in Table 1 below:

[0088] Table 1:

[0089]

[0090] From the above Table 1, it can be seen that the flame-retardant rubber prepared by the application has good mechanical properties and flame-retardant properties, and from the comparative examples 1-6, it can be seen that the raw material composition and the preparation method have an important influence on the properties.

[0091] ② The vibration isolator product prepared is a typical compression type vibration isolator, and the amount of flame-retardant rubber used for a single vibration isolator is about 1.1 kg. The flame-retardant rubber used is prepared by the application example 1;

[0092] The static and dynamic properties are tested using an Instron 8802 static and dynamic tester produced by the British Instron company, according to GB / T 15168-2013, and the test temperature is the standard ambient temperature;

[0093] The creep performance test: three vibration isolators are placed in a "pin" shape, and a load of 30kN is applied thereon, and the height of the vibration isolator is recorded by a dial gauge, and the data is recorded after 1h of loading, and the test is continuously conducted for 10d. The difference between the values obtained at 1h and at the end of the test is the creep value.

[0094] The test results are shown in Table 2 below:

[0095] Table 2:

[0096]

[0097] From the above Table 2, it can be seen that the flame-retardant rubber prepared by the application as a raw material for the vibration isolator has a low natural frequency and creep, and has a good vibration isolation effect.

[0098] The above examples are only used to illustrate the technical solutions of the application, and not to limit them; although the application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacements for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the application.

Claims

1. A flame-retardant rubber, characterized by, The composition comprises the following components in parts by weight: natural rubber 50-70 parts, solution styrene-butadiene rubber 25-35 parts, liquid phenyl silicone rubber 10-20 parts, white carbon black 30-40 parts, silane coupling agent Si-69 0.5-1.5 parts, stearic acid 1-3 parts, composite filler 30-50 parts, flame retardant 5-10 parts, polysiloxane grafted graphene 3-5 parts, antioxidant 0.5-1 part, sulfur 1-2 parts, accelerator 0.5-1 part; the flame retardant is DOPO-carbon nanotube composite; the preparation method of the DOPO-carbon nanotube composite is as follows: DOPO is heated to 130-140℃, after it is melted, 1,4-butenediol is added and reacted for 10-15h, then toluene is added, stirred for 0.5-1h, then methanol is added, continue to stir for 0.5-1h, filter, the obtained product is vacuum dried to constant weight to obtain an intermediate; carbon nanotubes are added into a mixed acid composed of sulfuric acid and concentrated nitric acid, ultrasonic oscillation is carried out at room temperature for 30-60min, then stirring is carried out at 70-85℃ for 4-8h, after dilution with water, filtration is carried out, washing is carried out until neutral, then vacuum drying is carried out, carboxylated carbon nanotubes are obtained, carbon nanotubes are added into dichlorosulfoxide, ultrasonic oscillation is carried out for 15-30min, then DMF is added, stirring is carried out at 65-75℃ for 36-48h, after removing the remaining dichlorosulfoxide by distillation under reduced pressure, the obtained product is washed with THF, vacuum drying is carried out, acyl chloride carbon nanotubes are obtained; the intermediate, acyl chloride carbon nanotubes and DMAC are mixed, ultrasonic oscillation is carried out for 15-30min, then pyridine is added dropwise, after heating reflux reaction for 36-48h, filtration is carried out, the obtained product is washed with DMAC, then vacuum drying to constant weight is carried out; the composite filler comprises aluminum hydroxide, magnesium hydroxide, zinc borate and zinc hydroxystannate; the mass ratio of the aluminum hydroxide, magnesium hydroxide, zinc borate and zinc hydroxystannate is 20-30:20-30:1-5:1-5; the preparation method of the polysiloxane grafted graphene is as follows: in a protective gas atmosphere, carboxylated graphene is added into toluene, ultrasonic dispersion is carried out, then hydroxyl-terminated polysiloxane and p-toluenesulfonic acid are added, after mixing uniformly, reaction is carried out at 100-120℃ for 8-12h, after the reaction is completed, vacuum filtration, toluene washing and vacuum drying are carried out.

2. The fire retardant rubber of claim 1 wherein, the liquid phenyl silicone rubber has a phenyl content of 10-20% and a viscosity of 3000-20000mPa·s.

3. The fire retardant rubber of Claim 1 wherein, the antioxidant comprises antioxidant RD and antioxidant 4020, the mass ratio of the antioxidant RD and the antioxidant 4020 is 1-3:1-3; the accelerator is accelerator NOBS and accelerator DTDM, the mass ratio of the accelerator NOBS and the accelerator DTDM is 3-5:

1.

4. The fire retardant rubber of Claim 1 wherein, the mass ratio of the carboxylated graphene, hydroxyl-terminated polysiloxane and p-toluenesulfonic acid is 15-20:24-50:

1.

5. A process for the preparation of a flame-retardant rubber according to any one of claims 1 to 4, characterized in that, The natural rubber is baked at 40-60℃ for 3-5h, and then mixed with the solution polymerized butadiene styrene rubber and the liquid phenyl silicone rubber after 10-15 times of thin passing. The initial temperature of the internal mixer is 70-80℃, and then the white carbon black, the silane coupling agent Si-69, the stearic acid and the antioxidant are added after 3-5min. The polysiloxane grafted graphene, the composite filler and the flame retardant are added after 1-2min. The rubber is discharged after mixing at 120-140℃ for 5-8min. Then, the sulfur and the accelerator are added on the open mill, and the rubber is thin passed for 6-10 times. The rubber is discharged and stored for 24h before vulcanization.

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