A ceramic silicone rubber composite material and its preparation method and application

Abstract

The present invention belongs to the technical field of fireproof materials, and specifically relates to a ceramic silicone rubber composite material and its preparation method and application. The raw material composition of the ceramic silicone rubber composite material includes a silicone rubber matrix, white carbon black, hydroxy silicone oil, flame retardant, expanded graphite, flux, ceramic filler and crosslinking agent. By introducing the expanded graphite functional additive, the expanded graphite of the composite material will remove oxygen-containing groups and generate gas after being overfired, causing the volume of the material to expand, thereby increasing the sealing extrusion force between the composite material and the sealing gap, improving the explosion-proof impact force of the ceramic silicone rubber, and effectively preventing the spread of flames and smoke; and the deoxidized expanded graphite has a regular molecular structure, so it has good thermal conductivity, can transfer heat to the flux and ceramic filler inside the material in time, which is conducive to reducing the ceramic temperature of the composite material, so that the ceramic structure is quickly formed inside the material, thereby improving the ceramic strength of the composite material.

Description

Technical Field

[0001] The invention belongs to the technical field of fireproof materials, and in particular relates to a ceramic silicone rubber composite material and a preparation method and application thereof. Background Art

[0002] Gap-filling fireproof materials are mainly used to seal or fill holes or gaps formed by penetration of buildings, structures and various types of power equipment. In the event of a fire, they can prevent the spread of flames, smoke and heat, and prevent the fire from being too large and causing major economic losses. Gap-filling fireproof materials have been widely used in power equipment, cable trenches, firewall gaps and other fields due to their fireproof, smoke-suppressing and easy construction characteristics.

[0003] Silicone rubber is a non-carbon-based rubber material with a main chain of Si-O structure. The Si-O bond breaking energy is 453.6 kJ / mol. Compared with the CC bond breaking energy (346.9 kJ / mol) in conventional carbon-based rubber materials, silicone rubber has a higher chemical bond breaking energy, so it has better high temperature resistance. In addition, when silicone rubber burns at high temperatures, it generates side chain peroxides, and then the substituents are cleaved and oxidized to generate solid SiO 2 , that is, no toxic gas is produced after combustion, and the heat release rate of silicone rubber is low, which makes it a rubber matrix material with excellent flame retardant application prospects. However, the only drawback is that silicone rubber generates SiO after excessive combustion. 2 The cohesive force between SiO 2 There are pores of different sizes between the particles. The solid products after combustion shrink in volume and are prone to cracking and pulverization, resulting in low bonding strength of the matrix and reduced effectiveness in preventing the spread of fire smoke. In extreme cases, they cannot withstand the impact force generated by the explosion of the burning materials, easily causing secondary disasters.

[0004] As people pay more and more attention to fire safety, ceramic rubber materials have received more and more attention. For example, Chinese patent document ZL201510073286.0 discloses a method for preparing ceramic fireproof and fire-resistant silicone rubber, and Chinese patent document ZL201610693781.6 discloses a ceramic composite belt with high anti-puncture, fireproof and fire-resistant properties and its preparation method. However, there are still two key technical problems in the prior art: first, in the ceramic silicone rubber component system, since flux, ceramic filler, etc. are inorganic filler components, it is difficult to disperse in the low-viscosity silicone rubber matrix and it is easy to form aggregates, forming defects in local areas, resulting in low strength of the ceramic rubber material; second, there is a certain temperature gradient on the surface and inside of the silicone rubber composite material, and the speed of forming the ceramic structure inside is slow, so that the silicone rubber matrix inside the material decomposes before the flux melts, and it is impossible to form a ceramic structure in the early stage of the fire. Therefore, it is urgent to develop a silicone rubber composite material for gap filling and plugging with high ceramic strength and low-temperature ceramicization. Summary of the invention

[0005] In view of this, the technical problem to be solved by the present invention is the defects of high ceramicization temperature and low ceramicization strength of the ceramicized rubber material in the prior art, and then by optimizing the formula of the ceramicized silicone rubber composite material, a silicone rubber composite material with high ceramicization strength and low-temperature ceramicization is provided.

[0006] Another object of the present invention is to provide a method for preparing a silicone rubber composite material having high ceramic strength and capable of low temperature ceramicization.

[0007] The objective of the present invention is achieved through the following technical solutions:

[0008] According to an embodiment of the present invention, in a first aspect, the present invention provides a ceramic silicone rubber composite material, wherein the raw material composition of the ceramic silicone rubber composite material comprises, by weight:

[0009] Silicone rubber matrix 100 parts

[0010] 10~50 parts of white carbon black

[0011] 1-5 parts of hydroxy silicone oil

[0012] Flame retardant 10-50 parts

[0013] Expanded graphite 5-10 parts

[0014] Flux 5-15 parts

[0015] 30~80 parts of porcelain filler

[0016] Cross-linking agent 0.5 to 5 parts.

[0017] In an embodiment of the present invention, the raw material composition of the ceramic silicone rubber composite material also includes: 5 to 10 parts of an organic modifier; the organic modifier is at least one of γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-aminopropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, and vinyltrimethoxysilane.

[0018] In an embodiment of the present invention, as a preferred implementation, the raw material composition of the ceramic silicone rubber composite material includes:

[0019] Silicone rubber matrix 100 parts

[0020] 40~50 parts of white carbon black

[0021] 2-5 parts of hydroxy silicone oil

[0022] Flame retardant 20-30 parts

[0023] Expanded graphite 5-8 parts

[0024] Flux 12-15 parts

[0025] Ceramic filler 70-80 parts

[0026] 8-10 parts of organic modifier

[0027] 2 to 5 parts of cross-linking agent.

[0028] In an embodiment of the present invention, further preferably, the raw material composition of the ceramic silicone rubber composite material includes:

[0029] 100 parts of silicone rubber matrix, 50 parts of white carbon black, 5 parts of hydroxy silicone oil, 20 parts of flame retardant, 5 parts of expanded graphite, 15 parts of flux, 80 parts of porcelain filler, 8 parts of organic modifier, and 2 parts of cross-linking agent.

[0030] In an embodiment of the present invention, further preferably, the raw material composition of the ceramic silicone rubber composite material includes:

[0031] 100 parts of silicone rubber matrix, 40 parts of white carbon black, 2 parts of hydroxy silicone oil, 30 parts of flame retardant, 8 parts of expanded graphite, 12 parts of flux, 70 parts of porcelain filler, 10 parts of organic modifier, and 5 parts of cross-linking agent.

[0032] In an embodiment of the present invention, the particle size of the expanded graphite is preferably 50 to 1000 meshes. The inventors have found that if the particle size of the expanded graphite is less than 50 meshes, the particle size is too large, it will become a stress concentration point locally, and it is difficult to form a uniformly dispersed filler network between the expanded graphite particles, affecting the tensile strength, compressive strength and thermal conductivity of the ceramic silicone rubber; and when the particle size is greater than 1000 meshes, the particle size is too small, the particle surface energy is high, and the expanded graphite itself is easy to self-aggregate to form aggregates, forming defects, affecting the expansion performance and thermal conductivity of the ceramic silicone rubber composite material.

[0033] In an embodiment of the present invention, optionally, the silicone rubber matrix is ​​a hydroxyl-terminated linear polyorganosiloxane with a molecular formula of HO(MeRSiO) n H, wherein the degree of polymerization n is 100 to 2000, R is at least one of methyl, vinyl, and phenyl, and the viscosity of the silicone rubber matrix is ​​10 4 ~10 6 m·Pas. The inventors have found that the degree of polymerization of the silicone rubber matrix affects the mixing effect between the matrix material and the added components and the strength of the composite material. When the degree of polymerization of the silicone rubber matrix is ​​lower than 100, the molecular weight is small and the matrix viscosity is low, resulting in low strength of the composite material; when the degree of polymerization is high, the molecular weight is large, the molecular chains are seriously entangled, and it is not conducive to the dispersion of the components.

[0034] In the embodiments of the present invention, white carbon black plays a reinforcing role in the composite material. When its specific surface area is too low, the particle size is large, the reinforcing effect is poor, and large-sized particles are prone to form defects. Such defects are prone to early damage when the material is subjected to external force, affecting the tensile strength and elongation at break of the silicone rubber matrix. When the specific surface area is high, the particle size is small and the reinforcing effect is good. However, due to the large specific surface area and high surface energy, the particles are easy to aggregate. Therefore, considering comprehensively, the specific surface area of ​​white carbon black is preferably 100 to 500 m 2 / g.

[0035] In the embodiment of the present invention, the hydroxyl groups in the hydroxyl silicone oil react with the hydroxyl groups on the surface of the white carbon black to improve the dispersibility of the white carbon black. If the hydroxyl content in the hydroxyl silicone oil is low, the modification effect is poor; while if the hydroxyl content is high, the modification effect is good, but at the same time, hydrogen bonds are formed between the hydroxyl groups in the hydroxyl silicone oil, affecting the modification effect on the white carbon black, and further affecting the strength of the material. Therefore, it is preferred that the hydroxyl content of the hydroxyl silicone oil is 5 to 10 wt%, and the viscosity is 50 to 1000 m·Pas.

[0036] In an embodiment of the present invention, optionally, the flame retardant is at least one of magnesium hydroxide, aluminum hydroxide, phosphite, polymetaphosphoric acid, boric acid, ammonium polyphosphate, sodium borate, and hexaphenoxycyclotriphosphazene.

[0037] In an embodiment of the present invention, optionally, the flux is at least one of glass powder, zinc borate, and boron oxide.

[0038] In an embodiment of the present invention, optionally, the porcelain filler is at least one of mica, montmorillonite, kaolin, wollastonite, calcium carbonate, and aluminum silicate fiber.

[0039] In an embodiment of the present invention, optionally, the crosslinking agent is at least one of tetraethyl orthosilicate, methyltriethoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, di-tert-butyl peroxide, diisopropylbenzene peroxide, and 2,5-dimethyl-2,5-di-tert-butyl peroxide hexane.

[0040] According to an embodiment of the present invention, in a second aspect, the present invention further provides a method for preparing the above-mentioned ceramic silicone rubber composite material, comprising the following steps:

[0041] A. mixing a silicone rubber matrix, white carbon black, hydroxy silicone oil and a flame retardant to obtain a pre-dispersed compound rubber;

[0042] B. Mixing expanded graphite, flux and ceramic filler to obtain a mixed filler; or, B1. Mixing expanded graphite, flux and ceramic filler, adding a solution containing an organic modifier to the resulting mixture, continuing to mix, filtering, collecting the filter cake, and drying to obtain an organically modified mixed filler;

[0043] C. The pre-dispersed rubber compound, the mixed filler and the cross-linking agent are mixed and stirred to prepare a rubber compound, and the rubber compound is molded to obtain the product.

[0044] In an embodiment of the present invention, to improve the dispersibility of the organic modifier in the mixed material powder, the organic modifier is mixed with a solution in the step B1 of the preparation method, preferably, the solution containing the organic modifier is an ethanol dispersion of the organic modifier, wherein the mass percentage of the organic modifier is 5-20%. The effect of the organic modifier is mainly to modify the expanded graphite, flux and porcelain filler to improve the dispersibility of these three components, but because the amount of the organic modifier is less, it is difficult to achieve the above purpose, so after the organic modifier is dispersed and diluted with ethanol in the present invention, the concentration of the organic modifier in the local area can be avoided to be too high, so that the organic modifier can be evenly dispersed in the mixed filler. If the concentration of the ethanol dispersion of the organic modifier is too high, it is not conducive to the uniformity of the combination of the organic modifier and the filler, and the too low concentration will introduce more ethanol into the filler, and the preparation cost is high.

[0045] In an embodiment of the present invention, in step B1 of the preparation method, ball milling is used for mixing, the rotation speed is 50-500rpm, and the ball milling time is 10-60min. The inventors have found that the process parameters of ball milling directly affect the dispersion of expanded graphite, flux and porcelain filler and the combination of organic modifier and mixed filler surface, so it is preferred that the ball milling speed and ball milling time are within a suitable range. Although the ball milling speed is too fast or the ball milling time is long, it is beneficial to the uniform dispersion of the mixed filler and the combination of organic modifier and mixed filler, but the mixing speed is high. The equipment requirements are high, resulting in high production costs, and too high mixing speed or too long ball milling time will also cause the temperature of the ball milling process to rise rapidly, and the temperature rise will promote the aggregation of the mixed filler after ball milling; while the lower ball milling speed and short ball milling time result in poor ball milling dispersion effect, which is not conducive to the dispersion and surface modification of the mixed filler.

[0046] In an embodiment of the present invention, in step B1 of the preparation method, the drying temperature is 100-200°C and the drying time is 30-120 minutes. The inventors have found that the drying temperature and time will affect the dispersibility of the mixed filler. If the drying temperature is too high or the drying time is too long, the energy is high, and aggregates are easily formed between the particles after drying, and the production cost is also high.

[0047] In an embodiment of the present invention, in step C of the preparation method, the stirring rate is 50-200 rpm, the temperature is 30-50°C, and the time is 5-30 min. The inventors have found that the stirring speed will affect the mixing degree of each component. If the stirring speed is too high, it will not only have high requirements on the equipment, but also produce strong shear force, which is easy to damage the matrix material; if the stirring speed is too low, the mixing effect is poor, which is not conducive to the uniform mixing of multiple components. In addition, the temperature during stirring will affect the mixed viscosity of the material. If the temperature is too low, the viscosity is high, which is not conducive to the mixing of various additive components with the silicone rubber matrix. If the temperature is too high, the material will undergo an early cross-linking reaction, affecting the material properties.

[0048] In an embodiment of the present invention, in step A of the preparation method, the mixing temperature is 100-200° C. and the mixing time is 30-120 min.

[0049] According to an embodiment of the present invention, in a third aspect, the present invention further provides the use of the above-mentioned ceramic silicone rubber composite material or the ceramic silicone rubber composite material prepared by the above-mentioned method in the fields of fire prevention, smoke suppression and flame retardancy.

[0050] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0051] 1. The ceramic silicone rubber composite material provided by the embodiment of the present invention comprises a specific amount of silicone rubber matrix, white carbon black, hydroxy silicone oil, flame retardant, expanded graphite, flux, ceramic filler and cross-linking agent. By introducing the expanded graphite functional additive, the expanded graphite of the composite material can remove oxygen-containing groups and generate gas after being burned, resulting in volume expansion of the material, thereby increasing the sealing extrusion force between the composite material and the sealed gap, improving the explosion-proof impact force of the ceramic silicone rubber, and effectively preventing the spread of flames and smoke; and the deoxidized expanded graphite has a regular molecular structure, so it has good thermal conductivity, and can transfer heat to the flux and ceramic filler inside the material in time, which is beneficial to reduce the ceramic temperature of the composite material, so that the ceramic structure is quickly formed inside the material, thereby improving the ceramic strength of the composite material, so that the ceramic silicone rubber composite material provided by the embodiment of the present invention can be used in the fields of fire prevention, smoke suppression, and flame retardancy.

[0052] 2. The ceramic silicone rubber composite material provided in an embodiment of the present invention also includes a specific amount of organic modifier in its raw material composition. By adding the organic modifier, the compatibility of inorganic components such as flux and ceramic filler with silicone rubber can be significantly improved, and the dispersion state of the inorganic filler can be improved, so that the composite material can form a more uniform and stable ceramic structure after firing, thereby improving the strength of the material after ceramicization.

[0053] 3. The ceramic silicone rubber composite material provided in an embodiment of the present invention preferably comprises 100 parts of silicone rubber matrix, 40-50 parts of white carbon black, 2-5 parts of hydroxy silicone oil, 20-30 parts of flame retardant, 5-8 parts of expanded graphite, 12-15 parts of flux, 70-80 parts of ceramic filler, 8-10 parts of organic modifier, and 2-5 parts of cross-linking agent, thereby obtaining a silicone rubber composite material with high ceramic strength and low ceramic temperature.

[0054] 4. The preparation method of the ceramic silicone rubber composite material provided in the embodiment of the present invention is carried out by mixing a silicone rubber matrix, white carbon black, hydroxy silicone oil and a flame retardant to obtain a pre-dispersed rubber compound, mixing expanded graphite, a flux and a ceramic filler to obtain a mixed filler, and then mixing the pre-dispersed rubber compound, the mixed filler and a cross-linking agent to obtain a rubber compound, and then subjecting the mixed filler to a molding process to obtain a ceramic silicone rubber composite material; the above-mentioned mixing method can achieve sufficient mixing of the raw materials, ensuring that the composite material obtained can form a ceramic structure at a relatively low temperature and has a relatively high ceramic strength, so that the ceramic silicone rubber composite material obtained according to the preparation method provided in the embodiment of the present invention can be used in the fields of fire prevention, smoke suppression, flame retardancy, etc.

[0055] 5. The preparation method of the ceramic silicone rubber composite material provided in the embodiment of the present invention improves the dispersibility of the inorganic filler by fully mixing the expanded graphite, flux, ceramic filler and the solution containing the organic modifier, so that the composite material can form a more uniform and stable ceramic structure after firing, thereby improving the strength of the material after ceramicization.

[0056] 6. The method for preparing the ceramic silicone rubber composite material provided in an embodiment of the present invention comprises the following steps: blending a silicone rubber matrix, white carbon black and hydroxy silicone oil at high temperature, utilizing the condensation reaction of hydroxyl groups in the hydroxy silicone oil with hydroxyl groups on the surface of white carbon black at high temperature to in-situ modify the white carbon black, thereby enhancing the reinforcing effect of white carbon black on the silicone rubber matrix and imparting excellent physical and mechanical strength to the silicone rubber matrix. DETAILED DESCRIPTION

[0057] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0058] If no specific experimental steps or conditions are specified in the examples of the present invention, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially. Unless otherwise specified, the "viscosity" in the present invention refers to the viscosity at 25°C.

[0059] Example 1

[0060] The ceramic silicone rubber composite material provided in this embodiment has the following raw material composition:

[0061]

[0062] This embodiment also provides a method for preparing a ceramic silicone rubber composite material, comprising the following steps:

[0063] (1) Methyl silicone rubber, fumed silica, hydroxy silicone oil, and magnesium hydroxide are mixed in an internal mixer at a mixing temperature of 150° C. for a mixing time of 60 min to obtain a pre-dispersed rubber mixture;

[0064] (2) placing expanded graphite, glass powder and mica ceramic filler in a ball mill, adding an ethanol dispersion of γ-mercaptopropyltrimethoxysilane with a mass percentage of 10wt% to the ball mill, then adding zirconium oxide grinding balls, placing the ball mill in a ball mill for ball milling and mixing, the ball mill speed is 200rpm, the ball milling time is 30min, after the ball milling is completed, filtering the mixed material, and then placing the filter cake in a vacuum drying oven for high-temperature drying treatment, the drying temperature is 150°C, and the time is 60min, to prepare an organically modified mixed filler;

[0065] (3) The pre-dispersed rubber compound obtained in step (1), the organically modified mixed filler obtained in step (2) and the ethyl orthosilicate crosslinking agent are placed in a vacuum mixer and mixed at a stirring speed of 100 rpm, a mixing temperature of 30° C. and a mixing time of 30 min to prepare a rubber compound; and then the rubber compound is molded to prepare the desired sample.

[0066] Example 2

[0067] The ceramic silicone rubber composite material provided in this embodiment has the following raw material composition:

[0068]

[0069]

[0070] This embodiment also provides a method for preparing a ceramic silicone rubber composite material, comprising the following steps:

[0071] (1) Methyl vinyl silicone rubber, precipitated silica, hydroxy silicone oil, phosphite, and polymetaphosphoric acid are mixed in an internal mixer at a mixing temperature of 200° C. for 30 min to obtain a pre-dispersed rubber mixture;

[0072] (2) placing expanded graphite, zinc borate and kaolin porcelain filler in a ball mill, adding 10% by weight of γ-aminopropyltriethoxysilane in ethanol dispersion to the ball mill, then adding zirconium oxide grinding balls, placing the ball mill in a ball mill for ball milling, the ball mill speed is 500 rpm, and the ball milling time is 30 minutes; after the ball milling is completed, filtering the mixed material, and then placing the filter cake in a vacuum drying oven for high-temperature drying treatment, the drying temperature is 200° C., and the time is 30 minutes, to prepare an organically modified mixed filler;

[0073] (3) The pre-dispersed rubber compound obtained in step (1), the organically modified mixed filler obtained in step (2) and the methyltriethoxysilane crosslinking agent are placed in a vacuum mixer and mixed at a stirring speed of 50 rpm, a mixing temperature of 40° C. and a mixing time of 20 min to prepare a rubber compound; and then the rubber compound is molded to prepare the desired sample.

[0074] Example 3

[0075] The ceramic silicone rubber composite material provided in this embodiment has the following raw material composition:

[0076]

[0077]

[0078] This embodiment also provides a method for preparing a ceramic silicone rubber composite material, comprising the following steps:

[0079] (1) placing methyl vinyl phenyl silicone rubber, fumed silica, hydroxy silicone oil, hexaphenoxy cyclotriphosphazene, and sodium borate in an internal mixer and mixing them at a mixing temperature of 150° C. for a mixing time of 120 min to obtain a pre-dispersed rubber mixture;

[0080] (2) Expanded graphite, boron oxide and wollastonite ceramic filler are placed in a ball mill, and a 5% by weight ethanol dispersion of vinyl trimethoxysilane is added to the ball mill, and then zirconium oxide grinding balls are added, and the ball mill is placed in a ball mill for ball milling and mixing, the ball mill speed is 200 rpm, and the ball milling time is 10 minutes. After the ball milling is completed, the mixed material is filtered, and then the filter cake is placed in a vacuum drying oven for high-temperature drying treatment, the drying temperature is 120°C, and the time is 100 minutes, to prepare an organically modified mixed filler;

[0081] (3) The pre-dispersed rubber compound, the organically modified mixed filler and the phenyltriethoxysilane crosslinking agent are placed in a vacuum mixer and mixed at a stirring speed of 150 rpm, a mixing temperature of 50° C. and a mixing time of 8 min to prepare a rubber compound; the rubber compound is then molded to prepare the desired sample.

[0082] Example 4

[0083] The ceramic silicone rubber composite material provided in this embodiment has the following raw material composition:

[0084]

[0085]

[0086] This embodiment also provides a method for preparing a ceramic silicone rubber composite material, comprising the following steps:

[0087] (1) placing methyl vinyl phenyl silicone rubber, fumed silica, hydroxy silicone oil, phosphite and ammonium polyphosphate in an internal mixer and mixing them at a mixing temperature of 150° C. for a mixing time of 120 min to obtain a pre-dispersed rubber mixture;

[0088] (2) placing expanded graphite, glass powder, mica, montmorillonite and calcium carbonate in a ball mill, adding an ethanol dispersion of γ-mercaptopropyltriethoxysilane with a mass percentage of 20% to the ball mill, then adding zirconium oxide grinding balls, placing the ball mill in a ball mill for ball milling and mixing, the ball mill speed is 100 rpm, and the ball milling time is 40 minutes; after the ball milling is completed, filtering the mixed material, and then placing the filter cake in a vacuum drying oven for high temperature treatment, the treatment temperature is 100° C., and the treatment time is 120 minutes, to prepare an organic modified mixed filler;

[0089] (3) The pre-dispersed rubber compound, the organically modified mixed filler and the diisopropylbenzene peroxide crosslinking agent are placed in a vacuum mixer and mixed at a stirring speed of 80 rpm, a mixing temperature of 40° C. and a mixing time of 20 min to prepare a rubber compound; and then the rubber compound is molded to prepare a sample.

[0090] Example 5

[0091] The ceramic silicone rubber composite material provided in this embodiment has the following raw material composition:

[0092]

[0093] This embodiment also provides a method for preparing a ceramic silicone rubber composite material, comprising the following steps:

[0094] (1) Methyl silicone rubber, fumed silica, hydroxy silicone oil, aluminum hydroxide, polymetaphosphoric acid, and boric acid are mixed in an internal mixer at a mixing temperature of 180° C. for 40 min to obtain a pre-dispersed rubber mixture;

[0095] (2) placing expanded graphite, glass powder, montmorillonite, and aluminum silicate fiber in a ball mill, adding an ethanol dispersion of γ-methacryloxypropyltrimethoxysilane with a mass percentage of 10% to the ball mill, then adding zirconium oxide grinding balls, placing the ball mill in a ball mill for ball milling and mixing, the ball mill speed is 300 rpm, and the ball milling time is 25 minutes; after the ball milling is completed, filtering the mixed material, and then placing the filter cake in a vacuum drying oven for high-temperature drying treatment, the drying temperature is 160° C., and the time is 40 minutes, to prepare an organic modified mixed filler;

[0096] (3) The pre-dispersed rubber compound, the organic modified mixed filler and the 2,5-dimethyl-2,5-di-tert-butyl peroxyhexane crosslinking agent are placed in a vacuum mixer and mixed at a stirring speed of 120 rpm, a mixing temperature of 40° C. and a mixing time of 25 min to prepare a rubber compound; the rubber compound is then molded to prepare the desired sample.

[0097] Example 6

[0098] The ceramic silicone rubber composite material provided in this embodiment has the following raw material composition:

[0099]

[0100] This embodiment also provides a method for preparing a ceramic silicone rubber composite material, comprising the following steps:

[0101] (1) Mixing methyl phenyl silicone rubber, fumed silica, hydroxy silicone oil and aluminum hydroxide in an internal mixer at a mixing temperature of 100° C. for 80 min to obtain a pre-dispersed rubber mixture;

[0102] (2) placing expanded graphite, boron oxide, and aluminum silicate fiber in a ball mill, adding zirconium oxide grinding balls, placing the ball mill in a ball mill for ball milling and mixing, the ball mill speed is 50 rpm, and the ball milling time is 60 min to obtain a mixed filler;

[0103] (3) The pre-dispersed rubber compound, the mixed filler and the phenyltrimethoxysilane crosslinking agent are placed in a vacuum mixer and mixed at a stirring speed of 200 rpm, a mixing temperature of 40° C. and a mixing time of 5 min to prepare a rubber compound; the rubber compound is then molded to prepare the desired sample.

[0104] Comparative Example 1

[0105] The raw material composition of the ceramic silicone rubber composite material in this comparative example is the same as that in Example 1, and the preparation method thereof is substantially the same as that in Example 1, except that the mixing temperature in step (1) is room temperature.

[0106] Comparative Example 2

[0107] The raw material composition of the ceramic silicone rubber composite material in this comparative example is the same as that in Example 1, and the preparation method thereof is substantially the same as that in Example 1, except that:

[0108] In step (2), the expanded graphite, glass powder, mica ceramic filler and an ethanol dispersion of γ-mercaptopropyltrimethoxysilane with a mass percentage of 10% are mixed, and the obtained mixture is directly filtered to obtain a filter cake.

[0109] Comparative Example 3

[0110] The raw material composition of the ceramic silicone rubber composite material in this comparative example is different from that in Example 2, except that no expanded graphite is added.

[0111] Accordingly, the only difference between the preparation method of the ceramic silicone rubber composite material in this comparative example and that in Example 2 is that no expanded graphite is added.

[0112] Experimental example

[0113] The performance tests were performed on the samples prepared in the above embodiments and comparative examples, and the results are shown in Table 1.

[0114] Tensile strength and elongation at break are properties of materials before being burned, while fire resistance limit, ceramicization temperature and ceramicization compressive strength are properties of materials after being burned.

[0115] The tensile strength and elongation at break tests are determined in accordance with the provisions of GB / T 528 Tensile stress-strain properties of vulcanized rubber or thermoplastic rubber.

[0116] The fire resistance limit test is carried out in accordance with the provisions of Section 6.16 of GB / T 23864 Fireproof Sealing Materials.

[0117] The ceramic compressive strength is tested in accordance with the requirements of Section 6.5 of GB / T 23864 Fireproof Sealing Materials.

[0118] The testing method of the ceramicization temperature is: placing the sample in a muffle furnace at different temperatures for high-temperature sintering, and observing whether a continuous hard shell is formed; the minimum temperature required to form a continuous hard shell is considered to be the ceramicization temperature.

[0119] Table 1

[0120]

[0121] As can be seen from Table 1, compared with Comparative Examples 1 to 3, Examples 1 to 6 have higher tensile strength and ceramic compression strength, lower ceramic temperature and longer fire resistance, which shows that the present invention can obtain a silicone rubber composite material with high ceramic strength and low-temperature ceramicization by optimizing the formula and / or preparation process of the ceramic silicone rubber composite material. The elongation at break is generally inversely proportional to the tensile strength, but the inventors have found that there are special cases between the two. The silicone rubber matrix has low strength and needs to rely on reinforcing fillers, mainly based on white carbon black. The interface adsorption effect is formed between the surface of the white carbon black and the silicone rubber molecules. When the rubber material is subjected to external force, the molecular chains adsorbed on the surface of the white carbon black particles slip microscopically with the external force, which plays a reinforcing role. If the surface modification of the white carbon black is good and the internal defects of the material are few, the tensile strength and elongation at break will also be high, as in Examples 3-4 of the present invention.

[0122] Compared with Comparative Example 1, the raw materials of Example 1 improve the mechanical strength of the composite material after high-temperature banburying, proving that the mechanical strength of the material is related to the dispersibility of the white carbon black reinforcing filler and the interface effect of white carbon black-silicone rubber. Compared with Comparative Example 2, after fully mixing the organic modifier with the inorganic filler in Example 1, it is beneficial to improve the fire resistance limit and ceramic compression strength of the composite material, which shows that the fire resistance limit and ceramic strength of the material are related to the amount and dispersibility of the flux and ceramic filler and the interface strength of the inorganic filler-silicone rubber. Comparing the fire resistance limit and ceramic compression strength of Example 2 and Comparative Example 3, it can be seen that the expanded graphite has a certain thermal conductivity, which is conducive to heat transfer and accelerates the formation of the ceramic structure inside the material, so that the ceramic compression strength and fire resistance limit of Example 2 are better than those of Comparative Example 3, proving that the present invention has technical advantages in the design of the composite material composition.

[0123] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A ceramic silicone rubber composite material, characterized in that: The raw material composition of the ceramic silicone rubber composite material includes, by weight: Silicone rubber matrix 100 parts 10~50 parts of white carbon black 1~5 parts of hydroxy silicone oil Flame retardant 10~50 parts Expanded graphite 5~10 parts Flux 5~15 parts Ceramic filler 30~80 parts Crosslinking agent 0.5~5 parts 5-10 parts of organic modifier; The organic modifier is at least one of γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-aminopropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane and vinyltrimethoxysilane; A method for preparing a ceramic silicone rubber composite material comprises the following steps: A. mixing a silicone rubber matrix, white carbon black, hydroxy silicone oil and a flame retardant to obtain a pre-dispersed compound rubber; The mixing temperature is 100-200°C; B1. The expanded graphite, flux and porcelain filler are mixed, a solution containing an organic modifier is added to the resulting mixture, mixing is continued, and then filtered, the filter cake is collected, and dried to obtain an organically modified mixed filler; The mixture is mixed by ball milling, with a rotation speed of 50-500 rpm and a ball milling time of 10-60 min; C. The pre-dispersed rubber compound, the mixed filler and the cross-linking agent are mixed and stirred to prepare a rubber compound, and the rubber compound is molded to obtain the product.

2. The ceramic silicone rubber composite material according to claim 1, characterized in that: The raw material composition of the ceramic silicone rubber composite material includes: Silicone rubber matrix 100 parts 40~50 parts of white carbon black 2~5 parts of hydroxy silicone oil Flame retardant 20~30 parts Expanded graphite 5~8 parts Flux 12~15 parts Ceramic filler 70~80 parts 8~10 parts of organic modifier 2~5 parts of cross-linking agent.

3. The ceramic silicone rubber composite material according to claim 2, characterized in that: The raw material composition of the ceramic silicone rubber composite material includes: 100 parts of silicone rubber matrix, 50 parts of white carbon black, 5 parts of hydroxy silicone oil, 20 parts of flame retardant, 5 parts of expanded graphite, 15 parts of flux, 80 parts of porcelain filler, 8 parts of organic modifier, 2 parts of cross-linking agent; or, 100 parts of silicone rubber matrix, 40 parts of white carbon black, 2 parts of hydroxy silicone oil, 30 parts of flame retardant, 8 parts of expanded graphite, 12 parts of flux, 70 parts of porcelain filler, 10 parts of organic modifier, and 5 parts of cross-linking agent.

4. The ceramic silicone rubber composite material according to claim 1, characterized in that: The particle size of the expanded graphite is 50 to 1000 mesh; and / or, The silicone rubber matrix is ​​a hydroxyl-terminated linear polyorganosiloxane with a molecular formula of HO(MeRSiO) n H, wherein the degree of polymerization n is 100-2000, R is at least one of methyl, vinyl, and phenyl, and the viscosity of the silicone rubber matrix is ​​10 4 ~10 6 m·Pas; and / or, The specific surface area of ​​the white carbon black is 100-500 m 2 / g; and / or, The hydroxy silicone oil has a hydroxy content of 5 to 10 wt % and a viscosity of 50 to 1000 m·Pas; and / or, The flame retardant is at least one of magnesium hydroxide, aluminum hydroxide, phosphite, polymetaphosphoric acid, boric acid, ammonium polyphosphate, sodium borate, and hexaphenoxy cyclotriphosphazene; and / or, The flux is at least one of glass powder, zinc borate and boron oxide; and / or, The porcelain filler is at least one of mica, montmorillonite, kaolin, wollastonite, calcium carbonate and aluminum silicate fiber; and / or, The crosslinking agent is at least one of ethyl orthosilicate, methyltriethoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, di-tert-butyl peroxide, diisopropylbenzene peroxide, and 2,5-dimethyl-2,5-di-tert-butyl peroxide hexane.

5. The method for preparing the ceramic silicone rubber composite material according to claim 1, characterized in that: The steps include: A. mixing a silicone rubber matrix, white carbon black, hydroxy silicone oil and a flame retardant to obtain a pre-dispersed compound rubber; The mixing temperature is 100-200°C; B1. The expanded graphite, flux and porcelain filler are mixed, a solution containing an organic modifier is added to the resulting mixture, mixing is continued, and then filtered, the filter cake is collected, and dried to obtain an organically modified mixed filler; The mixture is mixed by ball milling, with a rotation speed of 50-500 rpm and a ball milling time of 10-60 min; C. The pre-dispersed rubber compound, the mixed filler and the cross-linking agent are mixed and stirred to prepare a rubber compound, and the rubber compound is molded to obtain the product.

6. The method for preparing the ceramic silicone rubber composite material according to claim 5, characterized in that: In step B1, the solution containing the organic modifier is an ethanol dispersion of the organic modifier, wherein the mass percentage of the organic modifier is 5-20%; and / or, The drying temperature is 100-200° C. and the drying time is 30-120 min.

7. The method for preparing the ceramic silicone rubber composite material according to claim 5, characterized in that: In step C, the stirring rate is 50-200 rpm, the temperature is 30-50° C., and the time is 5-30 min; and / or, In step A, the mixing time is 30 to 120 minutes.

8. Use of the ceramic silicone rubber composite material according to any one of claims 1 to 4 or the ceramic silicone rubber composite material prepared by the method according to any one of claims 5 to 7 in the fields of fire prevention, smoke suppression and flame retardancy.

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