Silicone rubber material with high oil resistance and high fire resistance and preparation method thereof

Abstract

The invention discloses a silicone rubber material with high oil resistance and high fire resistance and a preparation method thereof. The silicone rubber material is prepared from the following raw materials in parts by mass: 100 parts of a silicone rubber base material, 1-10 parts of a fluxing agent, 10-50 parts of a flame retardant, 20-80 parts of fire-resistant and oil-resistant filler, 2-8 parts of a structured control agent, 1-5 parts of a catalyst and 0.1-2 parts of a vulcanizing agent, the fluxing agent is a product obtained by carrying out condensation reaction on alkoxy silane or polysiloxane and a boron-containing compound; the silicone rubber base material is a composition of methyl vinyl trifluoropropyl silicone rubber and non-fluorinated silicone rubber. Fluorine-containing silicone rubber and common silicone rubber are compounded to serve as a base material, the fluxing agent and the structured control agent are matched to achieve improvement of the oil resistance of the material, the fluxing agent and the structured control agent are matched to balance the compatibility between the base material and the auxiliaries, and the flame retardance and the oil resistance of the material are further improved; the silicone rubber material with excellent comprehensive properties such as mechanical property, flame retardant property and oil resistance is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of rubber materials, and in particular to a highly oil-resistant and highly fire-resistant silicone rubber material and a preparation method thereof. Background Art

[0002] At present, oil pipelines, mechanical processing, automotive sealing components, aircraft and ship engines are used in oil-resistant scenarios. Silicone rubber materials have excellent properties such as high and low temperature resistance, weather resistance, electrical insulation and fire retardancy, so they are used in construction engineering, aerospace, medical equipment and other fields.

[0003] However, silicone rubber materials have poor tolerance to oily solvents and cannot meet the requirements of more demanding oil-resistant scenarios. In particular, after being immersed in non-polar oils such as fuel, aviation hydraulic oil and kerosene, the Si-O bonds of silicone rubber are easily destroyed, causing the material to swell and resulting in a decrease in mechanical properties. This greatly limits the application of silicone rubber products in industries such as oil seal components and ship and aircraft engine oil pipelines. Therefore, there are stricter requirements for silicone rubber materials, which need to have good oil resistance while being fireproof and high temperature resistant.

[0004] CN118027682A discloses a flame retardant and oil resistant silicone rubber material and a preparation method thereof, wherein the flame retardant and oil resistant silicone rubber material comprises the following raw materials in parts by weight: 60-90 parts of methyl vinyl cyanopropyl silicone rubber, 10-20 parts of acrylate rubber, 10-30 parts of methyl phenyl silicone resin, 10-30 parts of high vinyl silicone oil, 10-30 parts of hydroxy silicone oil, 10-20 parts of zinc oxide, 10-20 parts of polytetrafluoroethylene, 5-10 parts of silicon dioxide, 5-10 parts of silane coupling agent, 15-30 parts of filler, and 15-30 parts of auxiliary agent. The prepared flame retardant and oil resistant silicone rubber material has excellent flame retardant properties and oil and heat resistance properties, and its tensile strength, maximum heat resistance temperature and other performance indicators are improved.

[0005] CN112592591A discloses an oil-resistant flame-retardant silicone rubber material, the raw materials of which include: methyl vinyl cyanopropyl silicone rubber, high vinyl silicone oil, polytetrafluoroethylene, lightweight filler, flame-retardant filler, reinforcing filler, curing agent, and pigment. The introduction of cyanopropyl improves the oil resistance of the raw rubber itself, and the polytetrafluoroethylene filler synergistically improves the oil resistance. However, the introduced cyanide-containing compound also has a great safety hazard, and the environmental protection and sustainability need to be improved. Summary of the invention

[0006] Aiming at the problem of insufficient oil resistance of silicone rubber, the present invention provides a silicone rubber material formula, wherein the silicone rubber material having excellent fireproof, flame retardant and oil resistant properties is obtained by the synergistic effect of a fluorine-containing silicone rubber base material, a flux and a structuring control agent.

[0007] To achieve the above object, the technical solution adopted by the present invention is: A highly oil-resistant and fire-resistant silicone rubber material, the silicone rubber material comprising the following raw materials in parts by mass: 100 parts of silicone rubber base material, 1-10 parts of flux, 10-50 parts of flame retardant, 20-80 parts of fire-resistant and oil-resistant filler, 2-8 parts of structuring control agent, 1-5 parts of catalyst and 0.1-2 parts of vulcanizing agent; The flux is a product of condensation reaction between alkoxysilane or polysiloxane and a boron-containing compound; the silicone rubber base material is a composition of methyl vinyl trifluoropropyl silicone rubber and non-fluorine silicone rubber.

[0008] In the present invention, a composite of fluorine-containing silicone rubber and ordinary silicone rubber is used as a base material, and a flux and a structural control agent are used together to improve the oil resistance of the material. Due to the extremely strong electron-withdrawing effect of fluorine atoms in the fluorine-containing rubber, the fluorine-containing groups form an umbrella-like structure, which has a good shielding effect on the siloxane main chain and CC bond of the silicone rubber base material, so that a highly oil-resistant and highly fire-resistant silicone rubber material has good oil resistance.

[0009] The flux is a compound containing silicon radicals, which has excellent compatibility with silicone rubber and improves the dispersion of fillers in the base material. The addition of catalyst bismuth-molybdenum-doped magnesium-cobalt-nickel-copper-zinc oxide improves the density of the material and the dispersion of inorganic fillers in the silicone rubber material; it promotes the organic-inorganic transformation of the silicone rubber matrix and produces more decomposition products. The material can form a relatively compact ceramic structure at high temperature or when burned. The structure control agent performs surface treatment on the base material and inorganic filler, reduces the polarity of the CF of the fluorine-containing rubber, improves the dispersion of the flame retardant and refractory filler in the silicone rubber base material, and further improves the fire resistance, oil resistance and flame retardancy.

[0010] The mass proportion of methyl vinyl trifluoropropyl silicone rubber in the silicone rubber base material is 30-70%, and the mass proportion of non-fluorine silicone rubber is 30-70%. The content of fluorine-containing silicone oil should not be too high, and within this range, oil resistance, flame retardancy and mechanical properties can be guaranteed.

[0011] The non-fluorine silicone rubber includes one or more of dimethyl silicone rubber, methyl vinyl silicone rubber, and methyl phenyl vinyl silicone rubber; The Shore hardness of the silicone rubber base material is 40-60A; The alkoxysilane includes one or more of dimethyldichlorosilane, dimethyldimethoxysilane, vinyltriethoxysilane, phenyldimethoxysilane and tetraethoxysilane; The polysiloxane includes one or more of hydroxy polydimethylsiloxane and hydroxy polymethyl trifluoropropyl silicone resin; The boron-containing compound includes one or more of boric acid, tributyl borate, trimethyl borate and fluoroboric acid; The mass ratio of alkoxysilane or polysiloxane to the boron-containing compound in the flux is 100:0.1-100:8.

[0012] The flux preparation process comprises: mixing alkoxysilane or polysiloxane and a boron-containing compound at 80-200° C. for reaction for 0.5-4 hours, and then reacting in an oven at 120-180° C. for 4-8 hours.

[0013] The flame retardant includes one or more of aluminum hydroxide, magnesium hydroxide, phosphate, phosphite and ammonium polyphosphate; The fire-resistant and oil-resistant filler includes one or more of mullite, vermiculite powder, silica powder, polytetrafluoroethylene powder, and ferric oxide; the fire-resistant and oil-resistant filler is a mixture of any one of mullite, vermiculite powder, silica powder, polytetrafluoroethylene powder, and ferric oxide.

[0014] The structural control agent includes one or more of hydroxy fluorosilicone oil, methoxy silicone oil, vinyl trimethoxy silane and methyl trimethoxy silane; The catalyst comprises one or more of bismuth-molybdenum-doped magnesium-cobalt-nickel-copper-zinc oxide and cobalt-manganese-doped nickel-magnesium-copper ferrite; The vulcanizing agent includes one or more of di-tert-butyl peroxide, benzoyl peroxide, 2,5-dimethyl-2,5-di-tert-butyl peroxyhexane, 2,4-dichlorobenzoyl peroxide and platinum vulcanizing agent; The structural control agent is a mixture of hydroxymethyl fluorosilicone oil and one or more of methoxysilane, vinyl trimethoxysilane and methyl trimethoxysilane; wherein the mass ratio of the hydroxymethyl fluorosilicone oil to the other silane is 1-3:5.

[0015] The present invention also provides a method for preparing the highly oil-resistant and fire-resistant silicone rubber material, comprising the steps of: Step 1, after plasticizing the silicone rubber base material, mixing it with a flux, a flame retardant, a fire-resistant and oil-resistant filler, a structuring control agent, and a catalyst, and then removing the glue to obtain a mixed silicone rubber; Step 2, mixing the mixed silicone rubber with a vulcanizing agent to obtain a silicone rubber sheet, and vulcanizing the sheet to obtain the highly oil-resistant and highly fire-resistant silicone rubber material.

[0016] In the present invention, the silicone rubber material is prepared by combining internal mixing and open mixing, so that all base materials and additives are effectively and evenly mixed. The preparation method is simple and can be mass-produced using existing industrial equipment.

[0017] In step 1, the plasticizing temperature is 50-120° C., the plasticizing time is 5-20 min, and the rotation speed is 30-120 rpm; In step 1, the mixing temperature is 50-160° C., the mixing time is 20-60 min, and the rotation speed is 30-120 rpm; In step 2, the refining temperature is 15-45° C., and the roller speed ratio during refining is 1:1-1.5; In step 2, the vulcanization temperature is 150-200° C., the vulcanization pressure is 5-15 MPa, and the vulcanization time is 5-20 min.

[0018] Compared with the prior art, the present invention has the following beneficial effects: (1) In the present invention, fluorine-containing silicone rubber is used to improve the oil resistance of the material, and a flux and a structure control agent are used to balance the compatibility between the base material and the additive, thereby further improving the flame retardancy and oil resistance of the material, thereby obtaining a silicone rubber material having excellent comprehensive properties of mechanical properties, flame retardancy and oil resistance;

[0019] (2) The preparation method of the silicone rubber material of the present invention is simple, the raw material cost is low, and it can be industrially produced and applied on a large scale.

[0020] Therefore, the present invention combines the use of a homemade flux and a modified inorganic material, and under the action of a catalyst, the prepared silicone rubber material has excellent fire resistance, flame retardancy, oil resistance, heat insulation and other functions, and also has good high and low temperature resistance, anti-oxidation and aging properties. Therefore, it is a highly oil-resistant and highly fire-resistant silicone rubber material with excellent comprehensive performance, which can be used in technical fields such as aircraft and ship engines, oil pipelines and mechanical processing, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is the SEM image of the highly oil-resistant and highly fire-resistant silicone rubber material prepared in Example 1.

[0022] Figure 2 This is the SEM image of the highly oil-resistant and fire-resistant silicone rubber material prepared in Comparative Example 1.

[0023] Figure 3 This is the SEM image of the highly oil-resistant and fire-resistant silicone rubber material prepared in Comparative Example 2. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with embodiment. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Those skilled in the art can make modifications or equivalent substitutions based on the understanding of the technical scheme of the present invention without departing from the spirit and scope of the technical scheme of the present invention, and all should be included in the protection scope of the present invention.

[0025] The raw materials used in the following specific embodiments are all purchased from the market.

[0026] Example 1 Step 1, take 40 parts by weight of methyl vinyl silicone rubber (Shore hardness of 50A) and 60 parts by weight of methyl vinyl trifluoropropyl silicone rubber (Shore hardness of 50A) as silicone rubber base materials and add them into an internal mixer, set the temperature of the internal mixer to 120°C, the speed to 60 rpm, and plasticize for 12 minutes.

[0027] Step 2, add 3 parts by mass of bismuth-molybdenum-doped magnesium-cobalt-nickel-copper-zinc oxide, 4 parts by mass of a structuring control agent and 8 parts by mass of a flux, and mix at 120° C. for 15 minutes; then add 12 parts by mass of vermiculite powder, 20 parts by mass of polytetrafluoroethylene powder and 2 parts by mass of ferric oxide, and mix at 120° C. for 20 minutes; then add 38 parts by mass of magnesium hydroxide, and mix at 120° C. for 12 minutes to obtain a silicone rubber compound.

[0028] The structural control agent is a mixture of 3 parts by mass of hydroxy fluorosilicone oil, 10 parts by mass of vinyl trimethoxy silane and 1 part by mass of methyl trimethoxy silane; The flux is a product obtained by stirring 100 parts by mass of hydroxy polydimethylsiloxane, 10 parts by mass of hydroxy polymethyl trifluoropropyl silicone resin and 2 parts by mass of boric acid at 120° C. for 2 hours, and then placing in a vacuum oven at 150° C. for reaction for 6 hours.

[0029] Step 3, add the silicone rubber compound to a small double-roll open mill (roller speed ratio 1:1.2), and after the rubber compound is rolled, add 1.3 parts by mass of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, and mix evenly on the open mill to obtain a silicone rubber sheet. Put the silicone rubber sheet into a mold, and then place the mold on a flat vulcanizer at a temperature of 175°C and a pressure of 10MPa for vulcanization for 12 minutes to obtain a highly oil-resistant and fire-resistant silicone rubber material.

[0030] The above-prepared high oil-resistant and high fire-resistant silicone rubber material was tested for mechanical, flame retardant, thermal conductivity and oil resistance properties. The mechanical performance test standard is: a universal material testing machine is used to test the mechanical properties of a high oil-resistant and high fire-resistant silicone rubber material, the sample size is 25 mm×4 mm×3 mm, and the sample loading speed is 200 mm / min;

[0031] The flame retardant test standard is: refer to GB / T10707-2008 standard, use a horizontal-vertical combustion test machine to test the flame retardant grade of a highly oil-resistant and highly fire-resistant silicone rubber material; The thermal conductivity test standard is: referring to GB / T10297-2015 standard, a laser thermal conductivity meter is used to test the thermal conductivity of a highly oil-resistant and fire-resistant silicone rubber material, and the sample size is 10 mm×10 mm×1 mm; The oil resistance test standard is: referring to GB / T1690-2010 standard, an electric constant temperature oil tank is used to test the oil resistance of a highly oil-resistant and fire-resistant silicone rubber material. The sample size is 55 mm×25 mm×3 mm. It is immersed in oil solvent for 24 hours to characterize the changes in its mass and volume before and after oil immersion.

[0032] The test results are as follows: tensile strength is 4.70MPa, elongation at break is 278%, flame retardancy level is V-0 under UL-94 standard, thermal conductivity is 0.15W / m·K, and after 24h of oil immersion, the mass change rate of silicone rubber material is 6.11%, and the volume change rate is 11.29%.

[0033] Example 2 Step 1, take 30 parts by weight of methyl vinyl silicone rubber (Shore hardness of 50A) and 70 parts by weight of methyl vinyl trifluoropropyl silicone rubber (Shore hardness of 50A) as silicone rubber base materials and add them into an internal mixer, set the temperature of the internal mixer to 100°C, the speed to 60rpm, and plasticize for 12 minutes.

[0034] Step 2: first add 2 parts by mass of bismuth-molybdenum-doped magnesium-cobalt-nickel-copper-zinc oxide, 3 parts by mass of a structuring control agent and 10 parts by mass of a flux to the rubber of step 1, and mix at 100° C. for 15 minutes; then add 15 parts by mass of vermiculite powder, 15 parts by mass of polytetrafluoroethylene powder and 3 parts by mass of ferric oxide, and mix at 100° C. for 20 minutes; then add 42 parts by mass of magnesium hydroxide, and mix at 100° C. for 12 minutes to obtain a silicone rubber compound.

[0035] The structural control agent is a mixture of 2 parts by mass of hydroxy fluorosilicone oil, 8 parts by mass of vinyl trimethoxy silane and 1 part by mass of methyl trimethoxy silane; The flux is a product obtained by stirring 100 parts by mass of hydroxy polydimethylsiloxane, 10 parts by mass of hydroxy polymethyl trifluoropropyl silicone resin and 1 part by mass of boric acid at 120° C. for 2 hours, and then placing in a vacuum oven at 150° C. for reaction for 6 hours.

[0036] Step 3, add the silicone rubber compound to a small double-roll open mill (roller speed ratio 1:1.2), and after the rubber compound is rolled, add 1.2 parts by mass of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, and mix evenly on the open mill to obtain a silicone rubber sheet. Put the silicone rubber sheet into a mold, and then place the mold on a flat vulcanizer at a temperature of 170°C and a pressure of 10MPa for vulcanization for 12 minutes to obtain a highly oil-resistant and fire-resistant silicone rubber material.

[0037] The highly oil-resistant and fire-resistant silicone rubber material prepared above was subjected to mechanical, flame retardant, thermal conductivity and oil resistance tests, and the results were as follows: tensile strength was 3.51 MPa, elongation at break was 163%, flame retardant grade under UL-94 standard was V-1, thermal conductivity was 0.19 W / m·K, and after 24 hours of oil immersion, the mass change rate of the silicone rubber material was 4.65%, and the volume change rate was 8.06%.

[0038] Example 3 Step 1, take 70 parts by weight of methyl vinyl silicone rubber (Shore hardness of 50A) and 30 parts by weight of methyl vinyl trifluoropropyl silicone rubber (Shore hardness of 40A) as silicone rubber base materials and add them into an internal mixer, set the temperature of the internal mixer to 100°C, the speed to 60rpm, and plasticize for 10 minutes.

[0039] Step 2: first add 4 parts by mass of bismuth-molybdenum-doped magnesium-cobalt-nickel-copper-zinc oxide, 2 parts by mass of a structuring control agent and 6 parts by mass of a flux to the rubber of step 1, and mix at 100° C. for 12 minutes; then add 25 parts by mass of vermiculite powder, 10 parts by mass of polytetrafluoroethylene powder and 2 parts by mass of ferric oxide, and mix at 100° C. for 15 minutes; then add 40 parts by mass of magnesium hydroxide, and mix at 100° C. for 12 minutes to obtain a silicone rubber compound.

[0040] The structural control agent is a mixture of 4 parts by mass of hydroxy fluorosilicone oil, 10 parts by mass of vinyl trimethoxy silane and 3 parts by mass of methyl trimethoxy silane; The flux is a product synthesized by condensation reaction of 100 parts by mass of hydroxy polydimethylsiloxane and 5 parts by mass of boric acid at 100°C-180°C.

[0041] Step 3, add the silicone rubber compound to a small double-roll open mill (roller speed ratio 1:1.2), and after the rubber compound is rolled, add 1 part by mass of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, and mix evenly on the small double-roll open mill to obtain a silicone rubber sheet. Put the silicone rubber sheet into a mold, and then place the mold on a flat vulcanizer at a temperature of 170°C and a pressure of 10MPa for vulcanization for 12 minutes to obtain a highly oil-resistant and fire-resistant silicone rubber material.

[0042] The highly oil-resistant and fire-resistant silicone rubber material prepared above was subjected to mechanical, flame retardant, thermal conductivity and oil resistance tests, and the results were as follows: tensile strength was 4.55 MPa, elongation at break was 262%, flame retardant grade was V-0 under UL-94 standard, thermal conductivity was 0.16 W / m·K, and after 24 hours of oil immersion, the mass change rate of the silicone rubber material was 13.61%, and the volume change rate was 25.45%.

[0043] Example 4 Step 1, take 30 parts by mass of methyl vinyl silicone rubber (Shore hardness of 50A), 20 parts by mass of methyl vinyl silicone rubber (Shore hardness of 40A) and 50 parts by mass of methyl vinyl trifluoropropyl silicone rubber (Shore hardness of 50A) as silicone rubber base materials and add them into an internal mixer, set the temperature of the internal mixer to 120°C, the speed to 60rpm, and plasticize for 14 minutes.

[0044] Step 2: first add 1 part by mass of bismuth-molybdenum-doped magnesium-cobalt-nickel-copper-zinc oxide, 2 parts by mass of a structuring control agent and 10 parts by mass of a flux to the rubber of step 1, and mix at 120° C. for 12 minutes; then add 17 parts by mass of vermiculite powder, 18 parts by mass of polytetrafluoroethylene powder and 6 parts by mass of ferric oxide, and mix at 120° C. for 20 minutes; then add 40 parts by mass of magnesium hydroxide, and mix at 120° C. for 12 minutes to obtain a silicone rubber compound.

[0045] The structural control agent is a mixture of 3 parts by mass of hydroxy fluorosilicone oil, 9 parts by mass of vinyl trimethoxy silane and 2 parts by mass of methyl trimethoxy silane; The flux is a product synthesized by condensation reaction of 90 parts by mass of hydroxy polydimethylsiloxane, 15 parts by mass of hydroxy polymethyl trifluoropropyl silicone resin and 2 parts by mass of boric acid at 100°C-180°C.

[0046] Step 3, add the silicone rubber compound to a small double-roll open mill (roller speed ratio 1:1.2), and after the rubber compound is rolled, add 1.3 parts by mass of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, and mix evenly on the open mill to obtain a silicone rubber sheet. Put the silicone rubber sheet into a mold, and then place the mold on a flat vulcanizer at a temperature of 180°C and a pressure of 12MPa for vulcanization for 14 minutes to obtain a highly oil-resistant and fire-resistant silicone rubber material.

[0047] The highly oil-resistant and fire-resistant silicone rubber material prepared above was subjected to mechanical, flame retardant, thermal conductivity and oil resistance tests, and the results were as follows: tensile strength was 4.46 MPa, elongation at break was 251%, flame retardant grade was V-0 under UL-94 standard, thermal conductivity was 0.17 W / m·K, and after 24 hours of oil immersion, the mass change rate of the silicone rubber material was 9.23%, and the volume change rate was 17.82%.

[0048] Example 5 Step 1, take 40 parts by mass of methyl vinyl silicone rubber (Shore hardness of 60A), 20 parts by mass of methyl vinyl silicone rubber (Shore hardness of 40A) and 40 parts by mass of methyl vinyl trifluoropropyl silicone rubber (Shore hardness of 40A) as silicone rubber base materials and add them into an internal mixer, set the temperature of the internal mixer to 150°C, the speed to 60rpm, and plasticize for 14 minutes.

[0049] Step 2, first add 1.5 parts by mass of bismuth-molybdenum-doped magnesium-cobalt-nickel-copper-zinc oxide, 5 parts by mass of a structuring control agent and 7 parts by mass of a flux to the rubber in step 1, and mix at 150° C. for 12 minutes; then add 10 parts by mass of vermiculite powder, 15 parts by mass of polytetrafluoroethylene powder, 8 parts by mass of silicon powder and 2 parts by mass of ferric oxide, and mix at 150° C. for 25 minutes; then add 43 parts by mass of magnesium hydroxide, and mix at 150° C. for 12 minutes to obtain a silicone rubber compound.

[0050] The structural control agent is a mixture of 2 parts by mass of hydroxy fluorosilicone oil, 6 parts by mass of vinyl trimethoxy silane and 1 part by mass of methyl trimethoxy silane; The flux is a product synthesized by condensation reaction of 80 parts by mass of hydroxy polydimethylsiloxane, 20 parts by mass of hydroxy polymethyl trifluoropropyl silicone resin and 3 parts by mass of boric acid at 100°C-180°C.

[0051] Step 3, add the silicone rubber compound to a small double-roll open mill (roller speed ratio 1:1.2), add 1.5 parts by mass of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane after the rubber compound is rolled, mix evenly on the open mill, and obtain a silicone rubber sheet. Put the silicone rubber sheet into a mold, and then place the mold on a flat vulcanizer at a temperature of 180°C and a pressure of 12MPa for vulcanization for 14 minutes to obtain a highly oil-resistant and fire-resistant silicone rubber material.

[0052] The mechanical, flame retardant and thermal conductivity tests of the highly oil-resistant and fire-resistant silicone rubber material prepared above showed that the tensile strength was 4.49 MPa, the elongation at break was 245%, the flame retardant grade under the UL-94 standard was V-0, the thermal conductivity was 0.20 W / m·K, and after 24 hours of oil immersion, the mass change rate of the silicone rubber material was 11.45%, and the volume change rate was 21.63%.

[0053] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that no catalyst is contained in this comparative example, and the other details are the same as Example 1, which will not be described again.

[0054] The highly oil-resistant and highly fire-resistant silicone rubber material obtained in this comparative example has a tensile strength of 4.33 MPa, an elongation at break of 215%, a flame retardancy level of V-1 under the UL-94 standard, and a thermal conductivity of 0.27 W / m·K.

[0055] Comparative Example 2 The only difference between Comparative Example 2 and Example 1 is that this comparative example does not contain a structuring control agent, and the rest is the same as Example 1, which will not be repeated here.

[0056] The highly oil-resistant and highly fire-resistant silicone rubber material obtained in this comparative example has a tensile strength of 4.02 MPa, an elongation at break of 231%, a flame retardancy level of V-1 under the UL-94 standard, and a thermal conductivity of 0.25 W / m·K.

[0057] Comparative Example 3 The only difference between Comparative Example 3 and Example 1 is that in this comparative example, the hydroxy fluorosilicone oil in the structured control agent is completely replaced by methyltrimethoxysilane, and the rest is the same as Example 1, which will not be repeated here.

[0058] The highly oil-resistant and highly fire-resistant silicone rubber material obtained in this comparative example has a tensile strength of 4.22 MPa, an elongation at break of 211%, a flame retardancy level of V-2 under the UL-94 standard, and a thermal conductivity of 0.20 W / m·K.

[0059] Comparative Example 4 The only difference between Comparative Example 4 and Example 1 is that 8 parts by mass of glass powder are used instead of 8 parts by mass of homemade flux in this comparative example, and the rest is the same as Example 1 and will not be repeated here.

[0060] The highly oil-resistant and highly fire-resistant silicone rubber material obtained in this comparative example has a tensile strength of 3.62 MPa, an elongation at break of 118%, a flame retardancy level of no level under the UL-94 standard, and a thermal conductivity of 0.34 W / m·K.

[0061] Comparative Example 5 The only difference between Comparative Example 5 and Example 1 is that 20 parts by mass of vermiculite powder is used instead of 20 parts by mass of polytetrafluoroethylene powder in this comparative example, and the other parts are the same as those in Example 1 and will not be described again.

[0062] The highly oil-resistant and highly fire-resistant silicone rubber material obtained in this comparative example has a tensile strength of 3.21 MPa, an elongation at break of 135%, a flame retardancy level of V-1 under the UL-94 standard, and a thermal conductivity of 0.21 W / m·K.

[0063] Comparative Example 6 The only difference between Comparative Example 6 and Example 1 is that 60 parts by mass of methyl vinyl silicone rubber (Shore hardness of 60A) is used instead of 60 parts by mass of fluorosilicone rubber in this comparative example, and the rest is the same as Example 1 and will not be repeated here.

[0064] The highly oil-resistant and highly fire-resistant silicone rubber material obtained in this comparative example has a tensile strength of 4.51 MPa, an elongation at break of 365%, a flame retardancy level of V-1 under the UL-94 standard, and a thermal conductivity of 0.23 W / m·K.

[0065] The performance data of the embodiments and comparative examples are summarized in Table 1. The highly oil-resistant and highly fire-resistant silicone rubber materials prepared in Example 1 and Comparative Examples 1-6 were subjected to an oil resistance test. The oil resistance test: the performance was measured after 24 hours of oil immersion according to the oil resistance test requirements for aircraft engine hoses and pipe assemblies (standard reference GB / T1690-2010). The test results are shown in Table 2 below.

[0066] Table 1 Comprehensive performance data of embodiments and comparative examples Serial number Tensile strength MPa Elongation at break % UL-94 Thermal conductivity W / m•K Example 1 4.70 278 V-0 0.15 Example 2 3.51 163 V-1 0.19 Example 3 4.55 262 V-0 0.16 Example 4 4.46 251 V-0 0.17 Example 5 4.49 245 V-0 0.20 Comparative Example 1 4.33 215 V-1 0.27 Comparative Example 2 4.02 231 V-1 0.25 Comparative Example 3 4.22 211 V-2 0.20 Comparative Example 4 3.62 118 No level 0.34 Comparative Example 5 3.21 135 V-1 0.21 Comparative Example 6 4.51 365 V-1 0.23 Table 2 Performance changes of silicone rubber material after 24h oil immersion treatment Serial number Quality change rate% Volume change rate% Loss of mechanical properties UL-94 before treatment UL-94 after treatment Example 1 6.11 11.29 Smaller V-0 V-0 Example 2 4.65 8.06 - V-1 - Example 3 13.61 25.45 - V-0 - Example 4 9.23 17.82 - V-0 - Example 5 11.45 21.63 - V-0 - Comparative Example 1 8.91 17.27 Larger V-1 V-2 Comparative Example 2 10.55 20.16 Larger V-1 V-2 Comparative Example 3 8.29 15.42 Larger V-2 V-1 Comparative Example 4 15.24 27.81 Larger No level No level Comparative Example 5 20.76 39.87 Larger V-1 V-1 Comparative Example 6 30.76 60.73 Larger V-1 No level The content of methyl vinyl trifluoropropyl silicone rubber in Example 2 is relatively high. Although it can further improve the oil resistance of the material, it is not good for the flame retardant and mechanical properties of the silicone rubber. If the content of fluorinated silicone rubber is further increased, the mechanical properties and flame retardant properties of the material may further decrease.

[0067] Comparison between Example 1 and Comparative Example 1 shows that the addition of bismuth-molybdenum-doped magnesium-cobalt-nickel-copper-zinc oxide can significantly improve the flame retardant properties of the highly oil-resistant and highly fire-resistant silicone rubber material, and the catalyst can give the highly oil-resistant and highly fire-resistant silicone rubber material a better oil resistance to a certain extent. Figure 1 As shown, the microscopic morphology of the material in Comparative Example 1 is as follows Figure 2 As shown, it can also be seen that the catalyst can improve the dispersion of the filler in the silicone rubber matrix, and there is no obvious agglomeration phenomenon, thereby improving the flame retardant properties of the highly oil-resistant and highly fire-resistant silicone rubber material, and the mechanical properties are also improved.

[0068] Comparison between Example 2 and Example 1 shows that the structured control agent can improve the mechanical and flame retardant properties of the highly oil-resistant and highly fire-resistant silicone rubber material, and the structured control agent can make the highly oil-resistant and highly fire-resistant silicone rubber material have more excellent oil resistance in the oil resistance test. Figure 1 As shown, the microscopic morphology of the material in Comparative Example 2 is as follows Figure 3 As shown, it can also be seen that the structuring control agent can improve the compatibility of the filler in the highly oil-resistant and highly fire-resistant silicone rubber material, and will not cause holes and agglomeration, thereby improving the mechanical properties and flame retardant properties of the highly oil-resistant and highly fire-resistant silicone rubber material.

[0069] Comparing Comparative Example 3 with Example 1, it can be seen that the fluorine-containing silicone oil in the structured control agent can improve the compatibility of the fluorine-containing material in the matrix, improve the flame retardant properties of the highly oil-resistant and highly fire-resistant silicone rubber material, and enable the highly oil-resistant and highly fire-resistant silicone rubber material to have more excellent oil resistance.

[0070] It can be seen from Comparative Example 4 that compared with Example 1, the synthesized flux has good compatibility with the silicone rubber base material, and improves the dispersibility of the refractory filler in the silicone rubber base material, so that a highly oil-resistant and highly fire-resistant silicone rubber material has good mechanical and flame retardant properties, and improves the oil resistance of a highly oil-resistant and highly fire-resistant silicone rubber material to a certain extent.

[0071] Comparison Example 5 shows that the polytetrafluoroethylene powder has good compatibility with the silicone rubber base material, and will be in-situ fiberized under strong mechanical shearing during the mixing process, thereby increasing the dispersibility of the filler in the silicone rubber base material and improving the mechanical and flame retardant properties of the composite material. The polytetrafluoroethylene powder contains a large number of fluorine atoms on the side groups of the molecular chain, which is conducive to further improving the medium resistance of the silicone rubber material.

[0072] Comparison between Example 6 and Example 1 shows that fluorosilicone rubber can greatly improve the oil resistance of highly oil-resistant and highly fire-resistant silicone rubber materials. Fluorosilicone rubber has fluorine-containing groups on its molecular chain, and its extremely strong electron-withdrawing effect can form an umbrella-like structure, which has a good shielding effect on the siloxane main chain and CC bonds, greatly improving the composite material's resistance to non-polar media.

[0073] The technical features of the above-described embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above-described embodiments are not described. In addition, the preparation method of the present invention is a mechanical blending process, and the auxiliary agents used do not contain pollutants, which has the advantages of being green and environmentally friendly and easy to realize industrialization. Although the present invention is disclosed as above, the protection scope disclosed by the present invention is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope disclosed by the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A highly oil-resistant and fire-resistant silicone rubber material, characterized in that: The silicone rubber material comprises the following raw materials in parts by mass: 100 parts of silicone rubber base material, 1-10 parts of flux, 10-50 parts of flame retardant, 20-80 parts of fire-resistant and oil-resistant filler, 2-8 parts of structural control agent, 1-5 parts of catalyst and 0.1-2 parts of vulcanizing agent; The flux is a product of condensation reaction between alkoxysilane or polysiloxane and a boron-containing compound; the silicone rubber base material is a composition of methyl vinyl trifluoropropyl silicone rubber and non-fluorine silicone rubber.

2. The highly oil-resistant and fire-resistant silicone rubber material according to claim 1, characterized in that: In the silicone rubber base material, the mass proportion of methyl vinyl trifluoropropyl silicone rubber is 30-70%, and the mass proportion of non-fluorine silicone rubber is 30-70%.

3. The highly oil-resistant and fire-resistant silicone rubber material according to claim 1, characterized in that: The non-fluorine silicone rubber includes one or more of dimethyl silicone rubber, methyl vinyl silicone rubber, and methyl phenyl vinyl silicone rubber; The Shore hardness of the silicone rubber base material is 40-60A.

4. The highly oil-resistant and fire-resistant silicone rubber material according to claim 1, characterized in that: The alkoxysilane includes one or more of dimethyldichlorosilane, dimethyldimethoxysilane, vinyltriethoxysilane, phenyldimethoxysilane and tetraethoxysilane; The polysiloxane includes one or more of hydroxy polydimethylsiloxane and hydroxy polymethyl trifluoropropyl silicone resin; The boron-containing compound includes one or more of boric acid, tributyl borate, trimethyl borate and fluoroboric acid; The mass ratio of alkoxysilane or polysiloxane to the boron-containing compound in the flux is 100:0.1-100:

8.

5. The highly oil-resistant and fire-resistant silicone rubber material according to claim 1, characterized in that: The flux preparation process comprises: mixing alkoxysilane or polysiloxane and a boron-containing compound at 80-200° C. for reaction for 0.5-4 hours, and then reacting in an oven at 120-180° C. for 4-8 hours.

6. The highly oil-resistant and fire-resistant silicone rubber material according to claim 1, characterized in that: The flame retardant includes one or more of aluminum hydroxide, magnesium hydroxide, phosphate, phosphite and ammonium polyphosphate; The fire-resistant and oil-resistant filler includes one or more of mullite, vermiculite powder, silica powder, polytetrafluoroethylene powder, and ferric oxide; The structural control agent includes one or more of hydroxy fluorosilicone oil, methoxy silicone oil, vinyl trimethoxy silane and methyl trimethoxy silane; The catalyst comprises one or more of bismuth-molybdenum-doped magnesium-cobalt-nickel-copper-zinc oxide and cobalt-manganese-doped nickel-magnesium-copper ferrite; The vulcanizing agent includes one or more of di-tert-butyl peroxide, benzoyl peroxide, 2,5-dimethyl-2,5-di-tert-butyl peroxyhexane, 2,4-dichlorobenzoyl peroxide and platinum vulcanizing agent.

7. The highly oil-resistant and fire-resistant silicone rubber material according to claim 1, characterized in that: The structural control agent is a mixture of hydroxymethyl fluorosilicone oil and one or more of methoxysilane, vinyl trimethoxysilane and methyl trimethoxysilane; wherein the mass ratio of the hydroxymethyl fluorosilicone oil to the other silane is 1-3:

5.

8. The method for preparing the highly oil-resistant and fire-resistant silicone rubber material according to any one of claims 1 to 7, characterized in that: Includes steps: Step 1, after plasticizing the silicone rubber base material, mixing it with a flux, a flame retardant, a fire-resistant and oil-resistant filler, a structuring control agent, and a catalyst, and then removing the glue to obtain a mixed silicone rubber; Step 2, mixing the mixed silicone rubber with a vulcanizing agent to obtain a silicone rubber sheet, and vulcanizing the sheet to obtain the highly oil-resistant and highly fire-resistant silicone rubber material.

9. The method for preparing a highly oil-resistant and fire-resistant silicone rubber material according to claim 8, characterized in that: In step 1, the plasticizing temperature is 50-120° C., the plasticizing time is 5-20 min, and the rotation speed is 30-120 rpm; In step 1, the mixing temperature is 50-160° C., the mixing time is 20-60 min, and the rotation speed is 30-120 rpm.

10. The method for preparing a highly oil-resistant and fire-resistant silicone rubber material according to claim 8, characterized in that: In step 2, the refining temperature is 15-45° C., and the roller speed ratio during refining is 1:1-1.5; In step 2, the vulcanization temperature is 150-200° C., the vulcanization pressure is 5-15 MPa, and the vulcanization time is 5-20 min.

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