High-temperature-resistant flame-retardant smoke-suppression silicone rubber and preparation method thereof

Abstract

The invention relates to high-temperature-resistant flame-retardant smoke-suppressing silicone rubber and a preparation method thereof. The silicone rubber comprises the following components in parts by weight: 50-70 parts of methyl vinyl silicone rubber; 5-10 parts of an organosilicon compound; 10-20 parts of an inorganic metal oxide; 20 to 30 parts of modified carbon black; 20 to 30 parts of a compound flame retardant; 4-6 parts of a vulcanizing agent; the modified carbon black is silanized carbon black; the compound flame retardant is formed by inserting zinc borate into graphite layers. Compared with the prior art, the obtained silicone rubber has good high-temperature stability and excellent aging resistance, through synergistic compounding of the modified carbon black, the compound flame retardant and the metal oxide, the effects of smoke suppression, flame retardance and high temperature resistance are achieved, the mechanical property of the silicone rubber is remarkably improved, and the service life of the silicone rubber is prolonged. The application range of the silicone rubber product is wider, and the economic value is good.

Description

Technical Field

[0001] The invention relates to the technical field of rubber, and in particular to a high temperature resistant, flame retardant and smoke suppressing silicone rubber and a preparation method thereof. Background Art

[0002] Silicone rubber is a semi-organic and semi-inorganic polymer material. The main chain of the molecular chain is composed of silicon atoms and oxygen atoms alternately, and the silicon atoms are connected to two organic side groups. It has the characteristics of organic and inorganic polymers and is one of the most important products of polysiloxane. Due to its good elasticity, weather resistance, electrical insulation and high temperature resistance, silicone rubber has been applied in many fields such as construction, machinery, electronic appliances, chemical industry, and aerospace.

[0003] Although silicone rubber has good heat resistance, it may experience slight degradation and increase in hardness when used above 300°C. In the prior art, metal oxides are generally added to silicone rubber, which can interact with the silicone rubber matrix at high temperatures to form a stable chemical bond or physical adsorption relationship. In a high temperature environment, these metal oxides can absorb heat, disperse stress, and can improve the overall high temperature resistance of silicone rubber through their own high melting point and thermal stability. However, the compatibility of metal oxides with silicone rubber is poor, which will affect the mechanical properties of silicone rubber, and the high temperature resistance performance is not significantly improved.

[0004] For example, CN114149689B discloses a heat-resistant additive for silicone rubber and its preparation method, which belongs to the field of silicone rubber. Its raw materials include: 90-110 parts of methylphenyl vinyl silicone rubber, 65-75 parts of hexamethyldisilazane, 15-20 parts of methylphenyl vinyl silicone oil, 8-10 parts of hexafluorobenzene, and 70-85 parts of metal inorganic compounds. Its preparation method includes the following steps: Step 1: weigh methylphenyl vinyl silicone rubber, methylphenyl vinyl silicone oil and hexafluorobenzene according to the ratio, stir and disperse them evenly at a temperature of 40±2°C to obtain an additive base material; Step 2: weigh hexamethyldisilazane and metal inorganic compounds according to the ratio and mix them with the additive base material, stir and react at a temperature of 150±3°C for 1-2h to obtain a heat-resistant additive for silicone rubber. The essence of this patent is to use the synergistic effect between multiple metal oxides to improve the high temperature resistance of silicone rubber, and its mechanical properties are poorly improved.

[0005] In view of this, this application is hereby filed. Summary of the invention

[0006] The purpose of the present invention is to provide a high temperature resistant, flame retardant and smoke suppressing silicone rubber and a preparation method thereof in order to overcome the poor high temperature resistance and mechanical properties of the silicone rubber in the prior art.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] The first aspect of the present invention provides a high temperature resistant flame retardant smoke suppression silicone rubber, comprising the following components in parts by weight:

[0009]

[0010] The modified carbon black is silanized carbon black;

[0011] The compound flame retardant is formed by inserting zinc borate between graphite layers.

[0012] Preferably, the modified carbon black comprises the following preparation steps:

[0013] The carbon black is added to a 30wt% nitric acid solution, ultrasonicated, heated for reaction, centrifugally washed and dried, and then the solid phase is dissolved in ethanol. After ultrasonication, a silane coupling agent is added, the pH is adjusted to 3-4, heated and stirred for reaction, and centrifugally washed and dried to obtain modified carbon black.

[0014] Preferably, the ratio of the carbon black, 30wt% nitric acid solution and silane coupling agent is 1g:(20-40ml):(1-10)g;

[0015] And / or, the silane coupling agent includes one or more of 3-aminopropyltriethoxysilane, γ-glycidyloxypropyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, and γ-mercaptopropyltrimethoxysilane;

[0016] And / or, the heating reaction temperature is 80-90°C and the time is 1-3h;

[0017] And / or, the temperature of the heating and stirring reaction is 90-100° C. and the time is 4-8 hours.

[0018] Preferably, the composite flame retardant comprises the following preparation steps:

[0019] Zinc borate and graphite are added to phosphoric acid, mixed evenly, potassium permanganate is added, heated in a water bath for reaction, filtered, washed and dried to obtain a composite flame retardant.

[0020] Preferably, the mass ratio of the zinc borate, graphite and potassium permanganate is 1g:(10-20g):(1-2g);

[0021] And / or, the temperature of the water bath heating reaction is 20-30° C. and the time is 4-8 h.

[0022] Preferably, the organosilicon compound includes one or more of methyl silicone oil, hydroxy silicone oil, and diphenylsilanediol;

[0023] And / or, the inorganic metal oxide includes one or more of iron oxide, titanium oxide, cerium oxide, and aluminum oxide;

[0024] And / or, the vulcanizing agent includes one or more of 1,1,3-trimethylcyclohexane, 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane.

[0025] The second aspect of the present invention provides a method for preparing a high temperature resistant, flame retardant and smoke suppressing silicone rubber, comprising the following steps:

[0026] S1, adding carbon black to a 30wt% nitric acid solution, ultrasonicating, heating for reaction, centrifugally washing and drying, dissolving the solid phase in ethanol, adding a silane coupling agent after ultrasonicating, adjusting the pH to 3-4, heating and stirring for reaction, centrifugally washing and drying to obtain modified carbon black;

[0027] S2, adding zinc borate and graphite to phosphoric acid, mixing evenly, adding potassium permanganate, heating in a water bath for reaction, filtering, washing and drying to obtain a composite flame retardant;

[0028] S3, mixing 50-70 parts by weight of methyl vinyl silicone rubber and 5-10 parts by weight of an organosilicon compound, and then adding 10-20 parts by weight of an inorganic metal oxide, 20-30 parts by weight of modified carbon black, 20-30 parts by weight of a compound flame retardant, and 4-6 parts by weight of a vulcanizing agent for plasticizing to obtain a rubber mixture;

[0029] S4, after vulcanizing the mixed rubber, cooling it to obtain high temperature resistant, flame retardant and smoke suppressing silicone rubber.

[0030] Preferably, in step S1, the ratio of the carbon black, 30wt% nitric acid solution and silane coupling agent is 1g: (20-40ml): (1-10)g;

[0031] And / or, in step S1, the silane coupling agent includes one or more of 3-aminopropyltriethoxysilane, γ-glycidyloxypropyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, and γ-mercaptopropyltrimethoxysilane;

[0032] And / or, in step S1, the silane coupling agent is γ-mercaptopropyltrimethoxysilane;

[0033] And / or, in step S1, the heating reaction temperature is 80-90°C and the time is 1-3h;

[0034] And / or, in step S1, the temperature of the heating and stirring reaction is 90-100°C and the time is 4-8h.

[0035] Preferably, in step S2, the mass ratio of the zinc borate, graphite and potassium permanganate is 1g:(10-20g):(1-2g);

[0036] And / or, in step S2, the temperature of the water bath heating reaction is 20-30° C. and the time is 4-8 hours.

[0037] Preferably, in step S3, the organosilicon compound includes one or more of methyl silicone oil, hydroxy silicone oil, and diphenylsilanediol;

[0038] And / or, in step S3, the inorganic metal oxide includes one or more of iron oxide, titanium oxide, cerium oxide, and aluminum oxide;

[0039] And / or, in step S3, the vulcanizing agent includes one or more of 1,1,3-trimethylcyclohexane, 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane;

[0040] And / or, in step S3, the mixing step includes:

[0041] After kneading at 40-60°C for 4-8 hours, increase the temperature to 120-140°C and knead for 1-3 hours;

[0042] And / or, in step S3, the step of plasticating includes:

[0043] Plasticize at 40-60℃ for 2-4h;

[0044] And / or, in step S4, the mixed rubber is vulcanized using a plate vulcanizing agent, the pressure of the plate vulcanizing agent is 25-30 MPa, and the temperature is 160-170°C.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] 1. The present invention firstly utilizes nitric acid to hydroxylate the surface of carbon black, and then adds a silane coupling agent to react with the hydroxyl group. The silane coupling agent first undergoes a hydrolysis reaction to generate silanol, and the hydroxyl groups in the silanol undergo a condensation reaction with the hydroxyl groups on the surface of the carbon black to form a siloxane bond. Silicone rubber is a high molecular polymer with a silicon-oxygen bond as the main skeleton, and its main chain is formed by alternately connecting silicon atoms and oxygen atoms. Therefore, the two have high compatibility. When mixed, the silanized carbon black will be uniformly dispersed in the silicone rubber matrix, and the siloxane groups of the two are cross-stacked to form a dense and stable structure, thereby improving the mechanical properties of the silicone rubber. In addition, the silane coupling agent in the present invention can form a three-layer structure of silylated carbon black-silane coupling agent-inorganic metal oxide by hydrogen bonding with a large number of hydroxyl groups on the surface of the inorganic metal compound (for example, a silane coupling agent containing an amino group can form hydrogen bonds with hydroxyl groups on the surface of the metal oxide). Since the silylated carbon black has good compatibility with silicone rubber, the siloxane bonds are cross-linked to form a network structure, so that the silylated carbon black can be evenly distributed in the silicone rubber, and the inorganic metal oxide is further dispersed in the silicone rubber, thereby improving the problem of poor compatibility between the metal oxide and the silicone rubber matrix.

[0047] In addition, the silicone rubber of the present invention is added with a compound flame retardant, which can synergistically improve the flame retardant effect with the inorganic metal oxide. At extremely high temperatures, the compound flame retardant expands rapidly at high temperatures, wherein the zinc borate between the graphite layers is thermally decomposed to generate boric acid, and further dehydrated to form boron trioxide, which softens into a molten state at 500°C and fills the interlayer gaps of the graphite after expansion, thereby improving the compactness and strength of the carbon layer. The carbon layer can better insulate heat and oxygen, prevent the chain reaction of free radicals, inhibit the combustion of silicone rubber, and thus reduce the generation of heat and smoke. In addition, the dense carbon layer can also effectively prevent smoke from escaping. Metal oxides are evenly dispersed in silicone rubber. When combustion occurs, they can form a dense metal oxide coating on the surface of the material, preventing oxygen from entering the interior of the material. At the same time, they can also block the escape of combustible gases, reduce the necessary conditions for combustion, and capture free radicals, etc., thereby achieving a flame retardant effect. When used in conjunction with a compound flame retardant, metal oxides can first act as catalysts to promote the cross-linking reaction of silicone rubber molecular chains, which helps to form coke, strengthen the carbon layer, and make the carbon layer dense. When metal oxides are used alone, they can only catalyze the formation of a carbon layer, and the formed carbon layer has cracks, which makes the flame retardant effect poor. However, this early carbon layer gives the compound flame retardant enough time to form a carbon layer. After the carbon layer is formed by cross-linking of silicone rubber, the compound flame retardant forms a carbon layer later. The double carbon layer synergistically retards and suppresses smoke.

[0048] Furthermore, pure metal oxides catalyze smoke particles, smoke precursors and carbon monoxide into CO2 in the gas phase, which is an important reason why metal oxides have a strong smoke suppression effect. The CO2 produced by metal oxide catalysis dilutes the concentration of combustible gases and slightly reduces the intensity of gas phase combustion, but this also leads to poor suppression of CO2 by metal oxides. The graphite in the compound flame retardant expands and produces non-combustible gases such as carbon dioxide, water and sulfur dioxide, which can dilute the concentration of combustible gases. At the same time, zinc borate absorbs heat and decomposes at high temperatures to produce water, which can dilute the concentration of combustible gases and achieve the effect of smoke suppression.

[0049] 2. The present invention achieves the effects of smoke suppression, flame retardancy and high temperature resistance through the synergistic compounding of modified carbon black, compound flame retardant and metal oxide, and significantly improves the mechanical properties of silicone rubber, thereby expanding the application range of silicone rubber products and having good economic value. DETAILED DESCRIPTION

[0050] For ease of understanding of the present application, the present application will be described more fully below by way of embodiments. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0051] For simplicity, this application only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an unclearly recorded range; and any lower limit can be combined with other lower limits to form an unclearly recorded range, and any upper limit can be combined with any other upper limit to form an unclearly recorded range. In addition, although not clearly recorded, each point or single value between the range endpoints is included in the range. Thus, each point or single value can be combined with any other point or single value as its own lower limit or upper limit or with other lower limits or upper limits to form an unclearly recorded range.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art in the technical field of the present application. The terms used herein in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. It should be noted that, unless otherwise specified, the term "and / or" used herein includes any and all combinations of one or more related listed items, and "above" and "below" include the number, and the meaning of "multiple" in "one or more" is more than two.

[0053] In the prior art, metal oxides are generally added to silicone rubber. They can interact with the silicone rubber matrix at high temperatures to form a stable chemical bond or physical adsorption relationship. In a high temperature environment, these metal oxides can absorb heat, disperse stress, and improve the overall high temperature resistance of silicone rubber through their own high melting point and thermal stability. However, the compatibility of metal oxides with silicone rubber is poor, which will affect the mechanical properties of silicone rubber, and the high temperature resistance performance is not significantly improved.

[0054] Based on this, the first aspect of the present application provides a high temperature resistant, flame retardant and smoke suppressing silicone rubber, comprising the following components in parts by weight:

[0055]

[0056] The modified carbon black is silanized carbon black;

[0057] The compound flame retardant is formed by inserting zinc borate between graphite layers.

[0058] In an optional embodiment, the modified carbon black comprises the following preparation steps:

[0059] The carbon black is added to a 30wt% nitric acid solution, ultrasonicated, heated for reaction, centrifugally washed and dried, and then the solid phase is dissolved in ethanol. After ultrasonication, a silane coupling agent is added, the pH is adjusted to 3-4, heated and stirred for reaction, and centrifugally washed and dried to obtain modified carbon black.

[0060] In an optional embodiment, the ratio of the carbon black, 30wt% nitric acid solution and silane coupling agent is 1g:(20-40ml):(1-10)g.

[0061] In an optional embodiment, the silane coupling agent includes one or more of 3-aminopropyltriethoxysilane, γ-glycidyloxypropyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, and γ-mercaptopropyltrimethoxysilane.

[0062] In an optional embodiment, the silane coupling agent is γ-mercaptopropyltrimethoxysilane.

[0063] In an optional embodiment, the heating reaction is carried out at a temperature of 80-90° C. and for a time of 1-3 h.

[0064] In an optional embodiment, the heating reaction is carried out at a temperature of 85° C. and for a time of 2 hours.

[0065] In an optional embodiment, the temperature of the heating and stirring reaction is 90-100° C. and the time is 4-8 hours.

[0066] In an optional embodiment, the temperature of the heating and stirring reaction is 95° C. and the time is 6 hours.

[0067] In an optional embodiment, the compound flame retardant comprises the following preparation steps:

[0068] Zinc borate and graphite are added to phosphoric acid, mixed evenly, potassium permanganate is added, heated in a water bath for reaction, filtered, washed and dried to obtain a composite flame retardant.

[0069] In an optional embodiment, the mass ratio of the zinc borate, graphite and potassium permanganate is 1g:(10-20g):(1-2g).

[0070] In an optional embodiment, the temperature of the water bath heating reaction is 20-30°C and the time is 4-8h.

[0071] In an optional embodiment, the temperature of the water bath heating reaction is 20-30°C and the time is 6 hours.

[0072] In an optional embodiment, the organic silicon compound includes one or more of methyl silicone oil, hydroxy silicone oil, and diphenylsilanediol.

[0073] In an optional embodiment, the inorganic metal oxide includes one or more of iron oxide, titanium oxide, cerium oxide, and aluminum oxide.

[0074] In an optional embodiment, the vulcanizing agent includes one or more of 1,1,3-trimethylcyclohexane, 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane.

[0075] The second aspect of the present application provides a method for preparing a high temperature resistant, flame retardant and smoke suppressing silicone rubber, comprising the following steps:

[0076] S1, adding carbon black to a 30wt% nitric acid solution, ultrasonicating, heating for reaction, centrifugally washing and drying, dissolving the solid phase in ethanol, adding a silane coupling agent after ultrasonicating, adjusting the pH to 3-4, heating and stirring for reaction, centrifugally washing and drying to obtain modified carbon black;

[0077] S2, adding zinc borate and graphite to phosphoric acid, mixing evenly, adding potassium permanganate, heating in a water bath for reaction, filtering, washing and drying to obtain a composite flame retardant;

[0078] S3, mixing 50-70 parts by weight of methyl vinyl silicone rubber and 5-10 parts by weight of an organosilicon compound, and then adding 10-20 parts by weight of an inorganic metal oxide, 20-30 parts by weight of modified carbon black, 20-30 parts by weight of a compound flame retardant, and 4-6 parts by weight of a vulcanizing agent for plasticizing to obtain a rubber mixture;

[0079] S4, after vulcanizing the mixed rubber, cooling it to obtain high temperature resistant, flame retardant and smoke suppressing silicone rubber.

[0080] In an optional embodiment, in step S1, the ratio of the carbon black, 30wt% nitric acid solution and silane coupling agent is 1g:(20-40ml):(1-10)g.

[0081] In an optional embodiment, in step S1, the silane coupling agent includes one or more of 3-aminopropyltriethoxysilane, γ-glycidyloxypropyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, and γ-mercaptopropyltrimethoxysilane.

[0082] In an optional embodiment, in step S1, the silane coupling agent is γ-mercaptopropyltrimethoxysilane.

[0083] In an optional embodiment, in step S1, the temperature of the heating reaction is 80-90°C and the time is 1-3h.

[0084] In an optional embodiment, in step S1, the temperature of the heating reaction is 85° C. and the time is 2 hours.

[0085] In an optional embodiment, in step S1, the temperature of the heating and stirring reaction is 90-100°C and the time is 4-8h.

[0086] In an optional embodiment, in step S1, the temperature of the heating and stirring reaction is 95° C. and the time is 6 hours.

[0087] In an optional embodiment, in step S2, the mass ratio of the zinc borate, graphite and potassium permanganate is 1g:(10-20g):(1-2g).

[0088] In an optional embodiment, in step S2, the temperature of the water bath heating reaction is 20-30° C. and the time is 4-8 h.

[0089] In an optional embodiment, in step S2, the temperature of the water bath heating reaction is 20-30°C and the time is 6 hours.

[0090] In an optional embodiment, in step S3, the organic silicon compound includes one or more of methyl silicone oil, hydroxy silicone oil, and diphenylsilanediol.

[0091] In an optional embodiment, in step S3, the inorganic metal oxide includes one or more of iron oxide, titanium oxide, cerium oxide, and aluminum oxide.

[0092] In an optional embodiment, in step S3, the vulcanizing agent includes one or more of 1,1,3-trimethylcyclohexane, 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane.

[0093] In an optional embodiment, in step S3, the mixing step includes:

[0094] After kneading at 40-60°C for 4-8 hours, the temperature was raised to 120-140°C and kneaded for 1-3 hours.

[0095] In an optional embodiment, in step S3, the step of plasticating includes:

[0096] Mastrate at 40-60°C for 2-4 hours.

[0097] In an optional embodiment, in step S4, the rubber mix is ​​vulcanized using a plate vulcanizing agent, the pressure of the plate vulcanizing agent is 25-30 MPa, and the temperature is 160-170°C.

[0098] The high temperature resistant, flame retardant and smoke suppressing silicone rubber of the present invention will be described in more detail below in conjunction with specific embodiments.

[0099] Example 1

[0100] This embodiment provides a method for preparing a high temperature resistant, flame retardant and smoke suppressing silicone rubber, comprising the following steps:

[0101] S1, add 5g of carbon black to 100ml of 30wt% nitric acid solution, ultrasonicate for 30min, heat to 85℃ in oil bath, react for 2h, centrifuge, wash and dry, dissolve the solid phase in ethanol, ultrasonicate for 30min, add 20g of 3-aminopropyltriethoxysilane, adjust pH to 3.5, heat to 95℃, stir and react for 6h, centrifuge, wash and dry to obtain modified carbon black;

[0102] S2, add 1g zinc borate and 20g graphite to 100ml phosphoric acid, mix well, add 1.84g potassium permanganate, heat to 25°C in a water bath for 6h, filter, wash and dry to obtain a composite flame retardant;

[0103] S3, mixing methyl vinyl silicone rubber and hydroxy silicone oil at a temperature of 50°C for 6 hours, raising the temperature to 120°C and mixing for 2 hours, then adding iron oxide, modified carbon black, compound flame retardant, and 1,1,3-trimethylcyclohexane and plasticizing at a temperature of 50°C for 3 hours to obtain a mixed rubber, wherein the mixed rubber comprises 60 parts of methyl vinyl silicone rubber, 8 parts of organosilicon compound, 15 parts of iron oxide, 25 parts of modified carbon black, 25 parts of compound flame retardant, and 5 parts of 1,1,3-trimethylcyclohexane;

[0104] S4, set the pressure of the flat vulcanizer to 30MPa and the temperature to 170℃, vulcanize the mixed rubber, after 15min, transfer it to an oven at 190℃ for reaction for 3h, take it out, and cool it naturally to obtain high temperature resistant, flame retardant and smoke suppression silicone rubber.

[0105] Example 2

[0106] This embodiment provides a method for preparing a high temperature resistant, flame retardant and smoke suppressing silicone rubber, comprising the following steps:

[0107] S1, add 5g of carbon black to 100ml of 30wt% nitric acid solution, ultrasonicate for 30min, heat to 85℃ in oil bath, react for 2h, centrifuge, wash and dry, dissolve the solid phase in ethanol, ultrasonicate for 30min, add 20g of 3-aminopropyltriethoxysilane, adjust pH to 3.5, heat to 95℃, stir and react for 6h, centrifuge, wash and dry to obtain modified carbon black;

[0108] S2, add 1g zinc borate and 20g graphite to 100ml phosphoric acid, mix well, add 1.84g potassium permanganate, heat to 25°C in a water bath for 6h, filter, wash and dry to obtain a composite flame retardant;

[0109] S3, mixing methyl vinyl silicone rubber and hydroxy silicone oil at a temperature of 50°C for 6 hours, raising the temperature to 120°C and mixing for 2 hours, then adding iron oxide, modified carbon black, compound flame retardant, and 1,1,3-trimethylcyclohexane and plasticizing at a temperature of 50°C for 3 hours to obtain a mixed rubber, wherein the mixed rubber comprises 70 parts of methyl vinyl silicone rubber, 8 parts of organosilicon compound, 15 parts of iron oxide, 30 parts of modified carbon black, 30 parts of compound flame retardant, and 5 parts of 1,1,3-trimethylcyclohexane;

[0110] S4, set the pressure of the flat vulcanizer to 30MPa and the temperature to 170℃, vulcanize the mixed rubber, after 15min, transfer it to an oven at 190℃ for reaction for 3h, take it out, and cool it naturally to obtain high temperature resistant, flame retardant and smoke suppression silicone rubber.

[0111] Example 3

[0112] This embodiment provides a method for preparing a high temperature resistant, flame retardant and smoke suppressing silicone rubber, comprising the following steps:

[0113] S1, add 5g of carbon black to 100ml of 30wt% nitric acid solution, ultrasonicate for 30min, heat to 85℃ in oil bath, react for 2h, centrifuge, wash and dry, dissolve the solid phase in ethanol, ultrasonicate for 30min, add 20g of 3-aminopropyltriethoxysilane, adjust pH to 3.5, heat to 95℃, stir and react for 6h, centrifuge, wash and dry to obtain modified carbon black;

[0114] S2, add 1g zinc borate and 20g graphite to 100ml phosphoric acid, mix well, add 1.84g potassium permanganate, heat to 25°C in a water bath for 6h, filter, wash and dry to obtain a composite flame retardant;

[0115] S3, mixing methyl vinyl silicone rubber and hydroxy silicone oil at a temperature of 50°C for 6 hours, raising the temperature to 120°C and mixing for 2 hours, then adding iron oxide, modified carbon black, compound flame retardant, and 1,1,3-trimethylcyclohexane and plasticizing at a temperature of 50°C for 3 hours to obtain a mixed rubber, wherein the mixed rubber comprises 50 parts of methyl vinyl silicone rubber, 8 parts of organosilicon compound, 15 parts of iron oxide, 20 parts of modified carbon black, 20 parts of compound flame retardant, and 5 parts of 1,1,3-trimethylcyclohexane;

[0116] S4, set the pressure of the flat vulcanizer to 30MPa and the temperature to 170℃, vulcanize the mixed rubber, after 15min, transfer it to an oven at 190℃ for reaction for 3h, take it out, and cool it naturally to obtain high temperature resistant, flame retardant and smoke suppression silicone rubber.

[0117] Example 4

[0118] This embodiment provides a method for preparing a high temperature resistant, flame retardant and smoke suppressing silicone rubber, comprising the following steps:

[0119] S1, add 5g of carbon black to 100ml of 30wt% nitric acid solution, ultrasonicate for 30min, heat to 85℃ in oil bath, react for 2h, centrifuge, wash and dry, dissolve the solid phase in ethanol, ultrasonicate for 30min, add 20g of γ-glycidyloxypropyltrimethoxysilane, adjust pH to 3.5, heat to 95℃, stir and react for 6h, centrifuge, wash and dry to obtain modified carbon black;

[0120] S2, add 1g zinc borate and 20g graphite to 100ml phosphoric acid, mix well, add 1.84g potassium permanganate, heat to 25°C in a water bath for 6h, filter, wash and dry to obtain a composite flame retardant;

[0121] S3, mixing methyl vinyl silicone rubber and hydroxy silicone oil at a temperature of 50°C for 6 hours, raising the temperature to 120°C and mixing for 2 hours, then adding iron oxide, modified carbon black, compound flame retardant, and 1,1,3-trimethylcyclohexane and plasticizing at a temperature of 50°C for 3 hours to obtain a mixed rubber, wherein the mixed rubber comprises 60 parts of methyl vinyl silicone rubber, 8 parts of organosilicon compound, 15 parts of iron oxide, 25 parts of modified carbon black, 25 parts of compound flame retardant, and 5 parts of 1,1,3-trimethylcyclohexane;

[0122] S4, set the pressure of the flat vulcanizer to 30MPa and the temperature to 170℃, vulcanize the mixed rubber, after 15min, transfer it to an oven at 190℃ for reaction for 3h, take it out, and cool it naturally to obtain high temperature resistant, flame retardant and smoke suppression silicone rubber.

[0123] Comparative Example 1

[0124] This comparative example provides a method for preparing a high temperature resistant, flame retardant and smoke suppressant silicone rubber, comprising the following steps:

[0125] S1, add 5g of carbon black to 100ml of 30wt% nitric acid solution, ultrasonicate for 30min, heat to 85℃ in oil bath, react for 2h, centrifuge, wash and dry, dissolve the solid phase in ethanol, ultrasonicate for 30min, add 20g of 3-aminopropyltriethoxysilane, adjust pH to 3.5, heat to 95℃, stir and react for 6h, centrifuge, wash and dry to obtain modified carbon black;

[0126] S2, mixing methyl vinyl silicone rubber and hydroxy silicone oil at a temperature of 50°C for 6 hours, raising the temperature to 120°C and mixing for 2 hours, then adding iron oxide, modified carbon black, and 1,1,3-trimethylcyclohexane and plasticizing at a temperature of 50°C for 3 hours to obtain a mixed rubber, wherein the methyl vinyl silicone rubber is 60 parts, the organosilicon compound is 8 parts, the iron oxide is 15 parts, the modified carbon black is 25 parts, and the 1,1,3-trimethylcyclohexane is 5 parts;

[0127] S3, set the pressure of the flat vulcanizer to 30MPa and the temperature to 170℃, vulcanize the mixed rubber, after 15min, transfer it to an oven at 190℃ for reaction for 3h, take it out, and cool it naturally to obtain high temperature resistant, flame retardant and smoke suppression silicone rubber.

[0128] Comparative Example 2

[0129] This comparative example provides a method for preparing a high temperature resistant, flame retardant and smoke suppressant silicone rubber, comprising the following steps:

[0130] S1, add 1g zinc borate and 20g graphite to 100ml phosphoric acid, mix well, add 1.84g potassium permanganate, heat in a water bath to 25°C for 6h, filter, wash and dry to obtain a composite flame retardant;

[0131] S2, mixing methyl vinyl silicone rubber and hydroxy silicone oil at a temperature of 50°C for 6 hours, raising the temperature to 120°C for mixing for 2 hours, then adding iron oxide, compound flame retardant, and 1,1,3-trimethylcyclohexane and plasticizing at a temperature of 50°C for 3 hours to obtain a mixed rubber, wherein the mixed rubber comprises 60 parts of methyl vinyl silicone rubber, 8 parts of organosilicon compound, 15 parts of iron oxide, 25 parts of compound flame retardant, and 5 parts of 1,1,3-trimethylcyclohexane;

[0132] S3, set the pressure of the flat vulcanizer to 30MPa and the temperature to 170℃, vulcanize the mixed rubber, after 15min, transfer it to an oven at 190℃ for reaction for 3h, take it out, and cool it naturally to obtain high temperature resistant, flame retardant and smoke suppression silicone rubber.

[0133] This comparative example provides a method for preparing a high temperature resistant, flame retardant and smoke suppressant silicone rubber, comprising the following steps:

[0134] Comparative Example 3

[0135] This comparative example provides a method for preparing a high temperature resistant, flame retardant and smoke suppressant silicone rubber, comprising the following steps:

[0136] S1, add 5g of carbon black to 100ml of 30wt% nitric acid solution, ultrasonicate for 30min, heat to 85℃ in oil bath, react for 2h, centrifuge, wash and dry, dissolve the solid phase in ethanol, ultrasonicate for 30min, add 20g of 3-aminopropyltriethoxysilane, adjust pH to 3.5, heat to 95℃, stir and react for 6h, centrifuge, wash and dry to obtain modified carbon black;

[0137] S2, add 1g zinc borate and 20g graphite to 100ml phosphoric acid, mix well, add 1.84g potassium permanganate, heat to 25°C in a water bath for 6h, filter, wash and dry to obtain a composite flame retardant;

[0138] S3, mixing methyl vinyl silicone rubber and hydroxy silicone oil at a temperature of 50°C for 6 hours, raising the temperature to 120°C for mixing for 2 hours, then adding modified carbon black, compound flame retardant, and 1,1,3-trimethylcyclohexane and plasticizing at a temperature of 50°C for 3 hours to obtain a mixed rubber, wherein the methyl vinyl silicone rubber comprises 60 parts, the organic silicon compound comprises 8 parts, the modified carbon black comprises 25 parts, the compound flame retardant comprises 25 parts, and the 1,1,3-trimethylcyclohexane comprises 5 parts;

[0139] S4, set the pressure of the flat vulcanizer to 30MPa and the temperature to 170℃, vulcanize the mixed rubber, after 15min, transfer it to an oven at 190℃ for reaction for 3h, take it out, and cool it naturally to obtain high temperature resistant, flame retardant and smoke suppression silicone rubber.

[0140] Comparative Example 4

[0141] This comparative example provides a method for preparing a high temperature resistant, flame retardant and smoke suppressant silicone rubber, comprising the following steps:

[0142] S1, add 1g zinc borate and 20g graphite to 100ml phosphoric acid, mix well, add 1.84g potassium permanganate, heat in a water bath to 25°C for 6h, filter, wash and dry to obtain a composite flame retardant;

[0143] S2, mixing methyl vinyl silicone rubber and hydroxy silicone oil at a temperature of 50°C for 6 hours, raising the temperature to 120°C for mixing for 2 hours, then adding iron oxide, carbon black, compound flame retardant, and 1,1,3-trimethylcyclohexane and plasticizing at a temperature of 50°C for 3 hours to obtain a mixed rubber, wherein the mixed rubber comprises 60 parts of methyl vinyl silicone rubber, 8 parts of organosilicon compound, 15 parts of iron oxide, 25 parts of carbon black, 25 parts of compound flame retardant, and 5 parts of 1,1,3-trimethylcyclohexane;

[0144] S3, set the pressure of the flat vulcanizer to 30MPa and the temperature to 170℃, vulcanize the mixed rubber, after 15min, transfer it to an oven at 190℃ for reaction for 3h, take it out, and cool it naturally to obtain high temperature resistant, flame retardant and smoke suppression silicone rubber.

[0145] Comparative Example 5

[0146] This comparative example provides a method for preparing a high temperature resistant, flame retardant and smoke suppressant silicone rubber, comprising the following steps:

[0147] S1, add 5g of carbon black to 100ml of 30wt% nitric acid solution, ultrasonicate for 30min, heat to 85℃ in oil bath, react for 2h, centrifuge, wash and dry, dissolve the solid phase in ethanol, ultrasonicate for 30min, add 20g of 3-aminopropyltriethoxysilane, adjust pH to 3.5, heat to 95℃, stir and react for 6h, centrifuge, wash and dry to obtain modified carbon black;

[0148] S2, after kneading methyl vinyl silicone rubber and hydroxy silicone oil at a temperature of 50°C for 6 hours, raising the temperature to 120°C and kneading for 2 hours, then adding iron oxide, modified carbon black, graphite, and 1,1,3-trimethylcyclohexane and plasticizing at a temperature of 50°C for 3 hours to obtain a mixed rubber, wherein the methyl vinyl silicone rubber is 60 parts, the organosilicon compound is 8 parts, the iron oxide is 15 parts, the modified carbon black is 25 parts, the graphite is 25 parts, and the 1,1,3-trimethylcyclohexane is 5 parts;

[0149] S3, set the pressure of the flat vulcanizer to 30MPa and the temperature to 170℃, vulcanize the mixed rubber, after 15min, transfer it to an oven at 190℃ for reaction for 3h, take it out, and cool it naturally to obtain high temperature resistant, flame retardant and smoke suppression silicone rubber.

[0150] Test Case

[0151] The hardness, tensile strength and tensile elongation of the silicone rubber in Examples 1 to 4 and Comparative Examples 1 to 5 were tested using GB / T528-2009. The test results are shown in Table 1.

[0152] The silicone rubber in Examples 1 to 4 and Comparative Examples 1 to 5 was subjected to a heat aging treatment at 300°C for 48 hours according to GB / T3512-2001. The hardness, tensile strength and elongation at break of the test samples after the heat aging treatment were tested. The test results are shown in Table 1.

[0153] The oxygen index of the silicone rubber in Examples 1 to 4 and Comparative Examples 1 to 5 was tested using GB / T107070-2008. The test results are shown in Table 2.

[0154] The smoke density of the silicone rubber in Examples 1 to 4 and Comparative Examples 1 to 5 was tested using GB / T8323.2-2008. The test results are shown in Table 2.

[0155] Table 1 Mechanical properties of silicone rubber of Examples 1 to 4 and Comparative Examples 1 to 5

[0156]

[0157] Table 2 Flame retardant properties of silicone rubber of Examples 1 to 4 and Comparative Examples 1 to 5

[0158] Examples Oxygen index (%) <![CDATA[Smoke density (Ds4 ignition)]]> <![CDATA[Smoke density (Ds4 non-ignition)]]> Example 1 35.8 71.2 132.4 Example 2 36.9 68.4 126.8 Example 3 35.1 73.8 136.9 Example 4 34.4 76.2 140.2 Comparative Example 1 25.7 538.4 618.9 Comparative Example 2 25.4 546.7 623.8 Comparative Example 3 25.1 555.8 634.1 Comparative Example 4 27.1 246.8 340.4 Comparative Example 5 26.8 285.4 342.5

[0159] It can be seen from Tables 1 and 2 above that the silicone rubber provided in the present application has good high temperature stability and excellent aging resistance, and through the synergistic compounding of modified carbon black, compound flame retardant, and metal oxide, not only the effects of smoke suppression, flame retardancy, and high temperature resistance are achieved, but also the mechanical properties of silicone rubber are significantly improved, so that the application range of silicone rubber products is wider and has good economic value.

[0160] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A high temperature resistant, flame retardant and smoke suppressing silicone rubber, characterized in that: It includes the following components by weight: The modified carbon black is silanized carbon black; The compound flame retardant is formed by inserting zinc borate between graphite layers.

2. The high temperature resistant, flame retardant and smoke suppressing silicone rubber according to claim 1, characterized in that: The modified carbon black comprises the following preparation steps: The carbon black is added to a 30wt% nitric acid solution, ultrasonicated, heated for reaction, centrifugally washed and dried, and then the solid phase is dissolved in ethanol. After ultrasonication, a silane coupling agent is added, the pH is adjusted to 3-4, heated and stirred for reaction, and centrifugally washed and dried to obtain modified carbon black.

3. The high temperature resistant, flame retardant and smoke suppressing silicone rubber according to claim 2, characterized in that: The ratio of the carbon black, 30wt% nitric acid solution and silane coupling agent is 1g: (20-40ml): (1-10)g; And / or, the silane coupling agent includes one or more of 3-aminopropyltriethoxysilane, γ-glycidyloxypropyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, and γ-mercaptopropyltrimethoxysilane; And / or, the heating reaction temperature is 80-90°C and the time is 1-3h; And / or, the temperature of the heating and stirring reaction is 90-100° C. and the time is 4-8 hours.

4. The high temperature resistant, flame retardant and smoke suppressing silicone rubber according to claim 1, characterized in that: The composite flame retardant comprises the following preparation steps: Zinc borate and graphite are added to phosphoric acid, mixed evenly, potassium permanganate is added, heated in a water bath for reaction, filtered, washed and dried to obtain a composite flame retardant.

5. The high temperature resistant, flame retardant and smoke suppressing silicone rubber according to claim 4, characterized in that: The mass ratio of the zinc borate, graphite and potassium permanganate is 1g: (10-20g): (1-2g); And / or, the temperature of the water bath heating reaction is 20-30° C. and the time is 4-8 h.

6. The high temperature resistant, flame retardant and smoke suppressing silicone rubber according to claim 1, characterized in that: The organosilicon compound includes one or more of methyl silicone oil, hydroxy silicone oil, and diphenylsilanediol; And / or, the inorganic metal oxide includes one or more of iron oxide, titanium oxide, cerium oxide, and aluminum oxide; And / or, the vulcanizing agent includes one or more of 1,1,3-trimethylcyclohexane, 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane.

7. A method for preparing high temperature resistant flame retardant and smoke suppressing silicone rubber, characterized in that: The following steps are involved: S1, adding carbon black to a 30wt% nitric acid solution, ultrasonicating, heating for reaction, centrifugally washing and drying, dissolving the solid phase in ethanol, adding a silane coupling agent after ultrasonicating, adjusting the pH to 3-4, heating and stirring for reaction, centrifugally washing and drying to obtain modified carbon black; S2, adding zinc borate and graphite to phosphoric acid, mixing evenly, adding potassium permanganate, heating in a water bath for reaction, filtering, washing and drying to obtain a composite flame retardant; S3, mixing 50-70 parts by weight of methyl vinyl silicone rubber and 5-10 parts by weight of an organosilicon compound, and then adding 10-20 parts by weight of an inorganic metal oxide, 20-30 parts by weight of modified carbon black, 20-30 parts by weight of a compound flame retardant, and 4-6 parts by weight of a vulcanizing agent for plasticizing to obtain a rubber mixture; S4, after vulcanizing the mixed rubber, cooling it to obtain high temperature resistant, flame retardant and smoke suppressing silicone rubber.

8. A method for preparing a high temperature resistant, flame retardant and smoke suppressing silicone rubber according to claim 7, characterized in that: In step S1, the ratio of the carbon black, 30wt% nitric acid solution and silane coupling agent is 1g:(20-40ml):(1-10)g; And / or, in step S1, the silane coupling agent includes one or more of 3-aminopropyltriethoxysilane, γ-glycidyloxypropyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, and γ-mercaptopropyltrimethoxysilane; And / or, in step S1, the silane coupling agent is γ-mercaptopropyltrimethoxysilane; And / or, in step S1, the heating reaction temperature is 80-90°C and the time is 1-3h; And / or, in step S1, the temperature of the heating and stirring reaction is 90-100°C and the time is 4-8h.

9. A method for preparing a high temperature resistant, flame retardant and smoke suppressing silicone rubber according to claim 7, characterized in that: In step S2, the mass ratio of the zinc borate, graphite and potassium permanganate is 1g:(10-20g):(1-2g); And / or, in step S2, the temperature of the water bath heating reaction is 20-30° C. and the time is 4-8 hours.

10. The method for preparing a high temperature resistant, flame retardant and smoke suppressing silicone rubber according to claim 7, characterized in that: In step S3, the organosilicon compound includes one or more of methyl silicone oil, hydroxy silicone oil, and diphenylsilanediol; And / or, in step S3, the inorganic metal oxide includes one or more of iron oxide, titanium oxide, cerium oxide, and aluminum oxide; And / or, in step S3, the vulcanizing agent includes one or more of 1,1,3-trimethylcyclohexane, 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane; And / or, in step S3, the mixing step includes: After kneading at 40-60°C for 4-8 hours, increase the temperature to 120-140°C and knead for 1-3 hours; And / or, in step S3, the step of plasticating includes: Plasticize at 40-60℃ for 2-4h; And / or, in step S4, the mixed rubber is vulcanized using a plate vulcanizing agent, the pressure of the plate vulcanizing agent is 25-30 MPa, and the temperature is 160-170°C.

Images