CN111117257A - Silicon rubber for automobile turbocharger tube and preparation method thereof - Google Patents
Silicon rubber for automobile turbocharger tube and preparation method thereof Download PDFInfo
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Abstract
The invention discloses a silicone rubber for an automobile turbocharger pipe, which comprises the following components in parts by weight: 100-130 parts of raw methyl vinyl silicone rubber; 60-80 parts of white carbon black; 10-20 parts of diatomite; 0.5-2.0 parts of nano cerium oxide; 1-5 parts of phenyl silicone oil; 5-10 parts of a structural control agent; 0.2-0.5 part of internal release agent; 0.5-2 parts of an organic peroxide vulcanizing agent. The invention also provides a preparation method of the silicone rubber for the automobile turbocharger tube. The silicone rubber for the automobile turbocharger pipe, which is prepared by the invention, has the advantages of high strength, low compression set, excellent high temperature resistance, excellent oil resistance and the like.
Description
[ technical field ] A method for producing a semiconductor device
The invention relates to the field of high polymer materials, and particularly relates to silicone rubber for an automobile turbocharger pipe and a preparation method thereof.
[ background of the invention ]
The turbocharged engine has the characteristics of sufficient fuel combustion, large power output, low emission and the like, conforms to the development trend of automobiles with energy conservation, emission reduction, safety and environmental protection, and is more and more widely applied. The temperature of compressed gas can be increased after leaving a compression chamber no matter the turbocharged engine adopts a mechanical supercharging system, an exhaust gas turbocharging system or a supercharging system, and the temperature of the compressed gas entering a gas outlet rubber pipe of the turbocharger is generally between 190 and 250 ℃; the gas is cooled between the compression chamber and the engine, the temperature of the cooled gas is different due to the difference of the inlet air temperature, the cooling effect of the intercooler and the pipeline arrangement, and the temperature of the gas generally entering the air outlet rubber pipe of the intercooler is 90-180 ℃.
The rubber tube for the automobile turbocharging system has the requirements on materials including high temperature resistance, oil resistance, high strength, low compression set and the like. This is because the turbo-charged gas is compressed and strongly rubbed to generate a high temperature, and even the cooled gas generally reaches a temperature of 100 ℃ or higher. Therefore, the rubber tube material applied to the turbocharging system must be capable of bearing higher temperature, and common natural rubber, styrene butadiene rubber and butadiene rubber cannot meet the use requirement under the high-temperature condition, so that a special high-temperature-resistant rubber material must be adopted. Secondly, the gas passing through the rubber hose of the turbocharging system is generally mixed with oil gas, so the rubber hose must have certain oil resistance, particularly high-temperature oil gas resistance. In addition, the turbocharging system not only has high temperature, but also has certain pressure, and in order to meet the requirements of production process and use assembly, the rubber tube rubber material of the turbocharging system is required to have higher tensile strength and tearing strength. Generally, the turbo-charging rubber pipe is connected with the metal pipe through a clamp to form a pipeline. At high temperature, rubber has good deformation resistance, otherwise, the clamp is loosened and the rubber tube falls off due to overlarge compression set, so that quality accidents are caused, and therefore, the rubber tube material for the automobile turbocharging system has low compression set.
Chinese patent CN103589100A discloses a turbo-charging rubber tube prepared by using fluorosilicone, which comprises the following components in percentage by mass: 20-30 parts of methyl vinyl silicone rubber; 35-45 parts of fluororubber premix; 5-7 parts of fluorosilicone resin; 2-3 parts of hydroxyl silicone oil; 1.5-2 parts of a peroxide vulcanizing agent; 0.5-1 part of a crosslinking assistant; 2-4 parts of precipitated white carbon black; 10-15 parts of carbon black (N990); 5-10 parts of magnesium oxide. The fluorosilicone gel prepared by the method has excellent heat resistance and oil resistance, but the fluorosilicone gel has a complex bonding process with silicone rubber, is low in bonding strength, and is fast in bonding strength reduction in a high-temperature environment.
Chinese patent CN104558807A discloses an ethylene acrylate rubber formula for a turbo-charging pipe, which is composed of the following raw materials in parts by weight: 70-90 parts of ethylene acrylate rubber; 10-30 parts of methyl vinyl silicone rubber; 1-2 parts of stearic acid; 30-60 parts of carbon black; 1-2 parts of an anti-aging agent; 1-2 parts of microcrystalline wax; 4-7 parts of a vulcanizing agent; 4-15 parts of fumed silica; 0.1-0.3 part of crosslinking assistant. The rubber composition prepared by the invention has good oil and gas resistance, excellent vibration damping performance and low compression permanent deformation, but has poor high and low temperature resistance, relatively high price, high process sensitivity and great difficulty in controlling the production process.
The silicon rubber has excellent high and low temperature resistance and can be used at the temperature of-50-250 ℃ for a long time, and the outstanding characteristic makes the silicon rubber become a preferred material for manufacturing the rubber tube of the turbocharging system; however, silicone rubber also has some disadvantages such as poor oil resistance, poor mechanical properties, and the like.
Therefore, the development of the silicone rubber for the automobile turbocharged engine, which has high strength, low compression set, excellent high temperature resistance and oil resistance, is of great significance.
[ summary of the invention ]
The invention aims to overcome the defects of the prior art and provide the silicone rubber for the automobile turbocharger tube, which has high strength, low compression set, excellent high-temperature resistance, excellent oil resistance and the like.
The invention is realized by the following technical scheme:
the silicone rubber for the automobile turbocharger pipe comprises the following components in parts by weight:
100-130 parts of raw methyl vinyl silicone rubber;
60-80 parts of white carbon black;
10-20 parts of diatomite;
0.5-2.0 parts of nano cerium oxide;
1-5 parts of phenyl silicone oil;
5-10 parts of a structural control agent;
0.2-0.5 part of internal release agent;
0.5-2 parts of an organic peroxide vulcanizing agent.
Further, the raw methyl vinyl silicone rubber has a vinyl content of 0.15-0.2% and a molar mass of 60-70 ten thousand g/mol.
Further, the particle size of the diatomite is 1-2 μm.
Further, the white carbon black is gas-phase hydrophilic white carbon black, and the BET specific surface area of the white carbon black is 150-380 m2/g。
Furthermore, the nano cerium oxide is gas-phase nano cerium oxide, and the particle size of the nano cerium oxide is 7-10 nm.
Further, the structural control agent is hydroxyl silicone oil. The hydroxyl silicone oil contains 3-4% of hydroxyl by mass and has a viscosity of 25-35 centipoises.
Further, the internal mold release agent is one or more of zinc stearate, stearic acid and calcium stearate.
Furthermore, the viscosity of the phenyl silicone oil is 300-400 centipoises.
Further, the organic peroxide vulcanizing agent is 2, 4-dichlorobenzoyl peroxide.
Furthermore, a small amount of silane coupling agent is added to improve the compatibility between the powder and the raw silicone rubber and improve the physical properties such as tensile strength and tearing strength.
In addition, the invention also provides a preparation method of the silicone rubber for the automobile turbocharger tube, which comprises the following steps:
A. adding diatomite into a high-speed stirrer, slowly stirring at the speed of 100r/min, dropwise adding a silane coupling agent, dispersing at the high speed of 1000r/min for 30min after dropwise adding, and then sealing and placing for more than 24h to obtain a material I;
B. adding all methyl vinyl silicone rubber crude rubber and partial white carbon black into a kneader, pouring a structural control agent and an internal mold release agent above the white carbon black, stirring and kneading the mixture into a mass, then respectively adding the rest white carbon black, the material I and the nano cerium oxide, and stirring the mixture to obtain a material II;
C. placing the material II at room temperature for a period of time, then pouring the material II into a kneader, adding phenyl silicone oil, heating and stirring, and then discharging and cooling to obtain a material III;
D. and adding an organic peroxide vulcanizing agent into the material III, and uniformly stirring to obtain the silicone rubber for the automobile turbocharger tube.
And C, stirring and kneading the mixture into a mass at 50-80 ℃, wherein the mass of the first added part of white carbon black is 10-30% of the total added white carbon black, the room-temperature standing time of the mixture II in the step C is more than 12 hours, the heating and stirring temperature is 150-175 ℃, and the heating and stirring time is 1.5-2.5 hours.
The design concept and mechanism of the present invention are explained in detail as follows:
the high-strength flame-retardant silicone rubber is prepared from raw methyl vinyl silicone rubber, white carbon black, diatomite, nano cerium oxide, phenyl silicone oil, a structural control agent, an internal mold release agent and an organic peroxide vulcanizing agent, and the prepared silicone rubber has high strength, low compression permanent deformation, excellent high-temperature resistance, excellent oil resistance and the like.
The raw methyl vinyl silicone rubber is a copolymer of dimethyl siloxane chain units and methyl vinyl siloxane chain units. Typically, the mole fraction of methylvinylsiloxane units in the copolymer is between 0.05% and 0.5%, which corresponds to about 5 to 50 methylvinylsiloxane units in 1 ten thousand siloxane units in the copolymer. The vulcanization activity of the silicone rubber can be effectively improved although the unsaturated group content is so small; the range of using organic peroxide is expanded, the vulcanization process of the original product is simplified, and the high-temperature aging resistance of the silicon rubber product is improved.
The methyl vinyl silicone rubber raw rubber provided by the invention has at least two silicon-bonded alkenyl groups in each molecule, does not contain silicon-bonded hydroxyl, and does not contain silicon-bonded alkoxy (the absence of silicon-bonded hydroxyl and alkoxy means that the molecular chain end of the raw rubber does not contain terminal hydroxyl and terminal methoxy groups). Because the terminal hydroxyl and the terminal methoxyl are easy to form hydrogen bonds with hydroxyl on the white carbon black, the structuralization degree of the rubber compound is greatly increased, and in addition, the vulcanized rubber is easy to adhere to a mold and causes difficult demolding due to too much terminal hydroxyl. The demoulding difficulty not only reduces the production efficiency, but also increases the breakage rate of the product. The presence of a large number of terminal hydroxyl groups also reduces the heat resistance of the vulcanizate.
The vinyl content of the raw methyl vinyl silicone rubber is 0.15-0.2%, and the preferable vinyl content is 0.16-0.18%.
The molar mass of the raw methyl vinyl silicone rubber is 60-70 ten thousand g/mol, preferably 65-70 ten thousand g/mol.
The molecular chain of raw silicon rubber is very soft, and the interaction between bonds is weak, so that its reinforcing effect is obviously different from that of general organic rubber, and the reinforcing filler is the necessary component for mixing silicon rubber.
White carbon black is a highly dispersed silica and is mainly used as a reinforcing filler which can impart sufficient mechanical strength to crosslinked silicone rubber.
The smaller the particle size of the white carbon black and the larger the specific surface area, the better the reinforcing effect. The white carbon black with the same particle size has greatly different chemical and physical properties, contained trace impurities and the like on the surface due to different preparation methods, so the reinforcing effect is greatly different. White carbon black is classified into a gas phase method (also called a combustion method) and a precipitation method (also called a wet method) according to the preparation method. The fumed silica is prepared by burning silicon tetrachloride in hydrogen and oxygen, generally contains trace hydrogen chloride, but has high purity; the mixed silicon rubber prepared by the composite material has very good electrical property, sealing heat resistance, fatigue durability, hot air vulcanization and high reinforcing effect. The precipitated white carbon black is prepared by reacting water glass (sodium silicate) in hydrochloric acid or sulfuric acid, generally contains a small amount of electrolyte which cannot be washed away by water, and has high water absorption; the mixed silicon rubber prepared by the method is inferior to the silicon rubber reinforced by fumed silica in the aspects of electrical property and heat resistance, and the foaming phenomenon is easy to generate during hot air vulcanization extrusion molding; but has small compression permanent deformation, small swelling property in oil and good rebound.
The content of the reinforcing filler in the composition according to the present invention is preferably 1 to 100 parts by weight, more preferably 30 to 50 parts by weight, based on 100 parts by weight of the raw methyl vinyl silicone rubber. If the amount is less than 1 part by weight, the mechanical strength of the crosslinked silicone rubber is insufficient, and if the amount exceeds 100 parts by weight, the silicone rubber becomes brittle.
The fumed silica is used as a reinforcing filler, the tensile strength of the mixed silicon rubber after vulcanization can reach a level of more than 10MPa, and the aim of improving the strength is to provide the tearing strength.
The white carbon black is fumed silica, and the BET specific surface area of the fumed silica is 150-380 m2A BET specific surface area of 200 to 300m is preferred2/g。
The invention also uses the diatomite and the white carbon black as mixed fillers, wherein the diatomite serves as a semi-reinforcing filler and an incremental filler, has high flame resistance, small water absorption and small particle size, and does not influence vulcanization and storage stability of the mixed silicon rubber. The diatomite is added mainly for the purpose of adjusting the hardness of the mixed silicon rubber, improving the processability and reducing the manufacturing cost.
Diatomaceous earth having an average particle diameter of 1 to 10 μm and a specific surface area of about 10m2The species/g has a slight reinforcing property, but cannot be blended in as large an amount as quartz powder. Since diatomaceous earth itself has lower hardness than quartz powder and is easily broken, it has low friction and is suitable for use as a silicone rubber member for oil seal.
The particle size of the diatomite is 1-2 mu m.
In the process of using the white carbon black as a reinforcing filler to prepare the hot vulcanized silicone rubber material, the active Si-OH groups contained on the surface of the white carbon black make the white carbon black and the raw rubber difficult to wet and difficult to mix; and Si-OH groups on the surface of the white carbon black and Si-O bonds in raw rubber molecules or Si-OH groups at chain ends can also form hydrogen bonds to generate physical adsorption and chemical combination, so that the prepared rubber gradually loses plasticity and processability in the storage process, and the phenomenon is called as structurization. In the process of preparing and mixing the silicon rubber material, a structuring control agent which can react with Si-OH groups on the surface of the white carbon black to make the white carbon black hydrophobic is added, so that the dispersion of the white carbon black in raw rubber can be improved, and the structuring of the rubber material can be inhibited.
The invention can select the structural control agents as follows: low molar mass hydroxyl terminated polydimethylsiloxanes, diphenylsilanediols, dimethyldialkoxysilanes, hexamethyldisilazane and other compounds containing silicon functional groups. The variety and the dosage of the structural control agent have great influence on the preparation process of the rubber material and the physical and mechanical properties of a vulcanized product, and the correct selection of the structural control agent and the reasonable use process are the keys for preparing the high-quality silicone rubber material.
According to the invention, the hydroxyl silicone oil is preferably used as a structural control agent, the viscosity of the hydroxyl silicone oil is 25-35 centipoise (cP), and the viscosity of the hydroxyl silicone oil is preferably 28-30 cP, so that the physical and mechanical properties of the silicone rubber can be improved. Compared with hexamethyl-silazane and other compounds containing silicon functional groups, the selected hydroxyl silicone oil has the advantages of low price, safety and small harm to the environment and human bodies. The viscosity of the hydroxyl silicone oil is selected, the viscosity is too low and is easy to volatilize, the viscosity is too high, the hydroxyl content is low, and the treatment effect is not obvious.
The oil resistance of the methyl vinyl silicone rubber can be improved by adding phenyl silicone oil with specific viscosity into the methyl vinyl silicone rubber, and the influence on other physical properties is small. Wherein the polymerization degree of the dimethyl silicone oil is 10-100. When the silicone rubber contacts fuel oil, the phenyl silicone oil can displace the fuel to inhibit swelling of the silicone rubber. The polymerization degree of the phenyl silicone oil cannot be more than 100, otherwise, the substitution effect is not generated; however, silicone oils with too low a viscosity (degree of polymerization below 10) are volatile during vulcanization of silicone rubber.
The viscosity of the phenyl silicone oil is 300-400 centipoises, and the preferred viscosity is 300-350 centipoises.
Cerium oxide is a light rare earth oxide which is cheap and has wide application, is used as a heat-resistant additive of mixed silicon rubber, has a very obvious effect of improving heat resistance when added in a small amount, and can be used for light-colored silicon rubber products. The preparation method of the nano cerium oxide mainly comprises a solid-phase sintering method, a liquid-phase method and a gas-phase method.
The solid phase sintering method is a traditional powder preparation process, is a method for preparing a product through solid-solid reaction at high temperature, has the advantages of high yield, simple and feasible preparation process and the like, but is generally used less because of the defects of high energy consumption, low efficiency, easy impurity mixing and the like. Compared with the solid phase method and the gas phase method, the liquid phase method has the characteristics of no need of harsh physical conditions, easy Chinese amplification, convenient operation and controllable particles, thereby having wide research. At present, the nano cerium oxide is mainly prepared by a precipitation method, a sol-gel method, a hydrothermal method, a micro-emulsion method, an ultrasonic chemical method, a spray reaction method and the like in a liquid phase method. The gas phase method refers to a method for generating a nano-scale new compound by chemical reaction of two or more simple substances or compounds in a gas phase. The vapor phase method includes a low-pressure gas evaporation method (gas condensation method), an active hydrogen-molten metal reaction method, a sputtering method, an evaporation method by heating with electricity, a volatile compound mixing method, a laser-induced chemical vapor deposition method, and the like.
The nano cerium oxide used in the invention is gas phase nano cerium oxide, the particle size of the nano cerium oxide is 7-10 nm, and the nano cerium oxide is beneficial to improving the high temperature resistance of the silicon rubber.
After the mixed silicon rubber is molded and formed, the product is easy to tear during demolding, and the surface of a metal mold is easy to be polluted after multiple times of molding. The solution is to add higher fatty acid or metal salt thereof as an internal mold release agent into the rubber compound. The internal release agents which can be selected in the invention are: lauric acid, stearic acid, palmitic acid, oleic acid, zinc stearate, magnesium stearate, calcium stearate, aluminum stearate, zinc laurate, magnesium laurate, sodium oleate, and the like. The dosage of the raw silicon rubber is 0.05-0.5 part by weight, and the raw silicon rubber can be added together with white carbon black and a structural control agent or added together with a vulcanizing agent before vulcanization.
When the mixed rubber using the higher fatty acid and the metal salt thereof as the internal release agent is used for preparing products with complex structures, particularly products with multiple moulds, the demoulding property is not ideal, the demoulding force is large, and the breakage rate of the products is high. If higher fatty acid and its metal salt are used in combination with water, hydrogen-containing silicone oil, methylphenyl silicone oil or hydroxy silicone oil, the mold release effect is significantly improved.
In the present invention, it is preferable that one or more of zinc stearate, stearic acid and calcium stearate are mixed as an internal mold release agent and used in cooperation with the hydroxy silicone oil. Zinc stearate, stearic acid and calcium stearate may be mixed in any proportion.
The mixed silicon rubber has no rubber characteristic before vulcanization, and only has the rubber characteristic by forming a three-dimensional network structure through chemical crosslinking under the action of a vulcanizing agent. Organic peroxide curatives useful in the present invention include: benzoyl Peroxide (BP), 2, 4-dichlorobenzoyl peroxide (DCBP), benzoyl peroxide tert-butyl ester (TBPB), di-tert-butyl peroxide (DTBP), dicumyl peroxide (DCP), 2, 5-dimethyl-2, 5-di-tert-butylperoxyhexane.
When peroxide is used as a vulcanizing agent for compounding silicone rubber, the amount of peroxide used is influenced by various factors, mainly depending on the type of raw rubber, the type and amount of filler, and the degree of crosslinking of the peroxide. The less the peroxide used, the better; however, the actual amount is often larger than the theoretical amount, and the influence of processing factors such as unevenness of the compounded silicone rubber, loss of peroxide during storage, hindrance of air and other compounding agents during vulcanization, and the like are mainly considered. The amount of peroxide should be reduced in a moderate amount as the vinyl content of the raw rubber increases. For some particular types of compounded silicone rubbers, two peroxides may be used in combination. In order to measure accurately and disperse uniformly, various vulcanizing agents are generally compounded into silicone oil or silicone rubber crude rubber paste with a certain mass fraction for use.
In the invention, the 2, 4-dichlorobenzoyl peroxide is preferably used as an organic peroxide vulcanizing agent, which is beneficial to improving the physical and mechanical properties of the silicone rubber.
The preferred scheme of the invention is as follows: 100-130 parts of raw methyl vinyl silicone rubber; 60-80 parts of white carbon black; 10-20 parts of diatomite; 0.5-2.0 parts of nano cerium oxide; 1-5 parts of phenyl silicone oil; 5-10 parts of hydroxyl silicone oil; 0.2-0.5 part of zinc stearate; 0.5-2 parts of 2, 4-dichlorobenzoyl peroxide.
The preferred preparation method of the invention is as follows:
A. adding diatomite into a high-speed stirrer, slowly stirring the mixed powder at the speed of 100r/min, dropwise adding a mixture (the mixing ratio is 1: 2) of vinyltrimethoxysilane and dimethyldimethoxysilane accounting for 1% of the mass of the diatomite, dispersing at the speed of 1000r/min for 30min after dropwise adding is finished, and then sealing and placing for more than 24h to obtain a material I;
B. adding all methyl vinyl silicone rubber crude rubber and partial white carbon black into a kneader, pouring hydroxyl silicone oil and zinc stearate above the white carbon black, stirring and kneading the mixture into a mass at the temperature of between 50 and 80 ℃ (cold stirring), and then adding the rest white carbon black, the material I and the nano cerium oxide in batches and stirring the mixture to obtain a material II;
C. placing the material II at room temperature for more than 12h, pouring the material II into a kneader, adding phenyl silicone oil, heating to 150-175 ℃, stirring for 1.5-2.5 h, discharging, and cooling to room temperature to obtain a material III;
D. and adding 2, 4-dichlorobenzoyl peroxide into the material III, and uniformly stirring to obtain the silicon rubber for the automobile turbocharging pipe.
During preparation of the product, the white carbon black is added in two parts, and the mass of the part of the white carbon black added for the first time in the step B is 10-30% of the total mass of the white carbon black, so that the white carbon black and the raw silicone rubber are fully and uniformly mixed.
The preparation method of the invention considers a plurality of factors and requirements of raw material cost, water and electricity consumption, safe production, large-scale production, environmental pollution and the like, takes the performance of the final product as a point of view, optimizes the original production process, and improves the selection of raw materials, the setting of each process parameter, the adding sequence of the raw materials and the like. Specifically, the treated diatomite which can be mixed with the raw silicone rubber of the invention and has good compatibility is added, and the nano cerium oxide and the phenyl silicone oil are added, which complement each other in terms of mechanism, so that the high temperature resistance and the oil resistance of the mixed silicone rubber are jointly improved.
In addition, the powder pretreatment in the step A of the invention mainly has the function of improving the compatibility of the diatomite and the silicon rubber, thereby improving the physical properties of the product. In the kneading and extruding process of step B, C, the purpose of standing at room temperature for 12h is to make the structuring agent hydroxy silicone oil completely diffuse to the surface of the white carbon black, so that the hydroxy treatment of the surface of the white carbon black is more complete, and the structuring phenomenon is reduced.
Compared with the prior art, the invention has the beneficial effects that:
1. according to the invention, the diatomite is treated by using the mixture of the vinyltrimethoxysilane and the dimethyl dimethoxysiloxane in the preparation of the silicon rubber for the automobile turbocharger tube, so that the dispersibility of the diatomite in the silicon rubber can be improved, and the tensile strength and the tear strength of the silicon rubber can be improved.
2. The phenyl silicone oil used in the preparation of the silicone rubber for the automobile turbocharger pipe has no reactivity, does not participate in crosslinking during vulcanization, exists in a vulcanized product in the form of a plasticizer, has good compatibility with lubricating oil, can be mutually replaced with the lubricating oil when contacting the lubricating oil, reduces the swelling property of the silicone rubber, and improves the oil resistance of the silicone rubber.
3. The nano cerium oxide used in the preparation of the silicone rubber for the automobile turbocharger tube is used as a heat-resistant additive, and can improve the thermal decomposition temperature of raw rubber, so that the service temperature of the silicone rubber is improved, and the service life of a silicone rubber product is prolonged.
4. The preparation method disclosed by the invention is simple in process control, easy to operate, safe, reliable, small in environmental pollution and suitable for batch production.
[ detailed description ] embodiments
The present invention will be further described with reference to the following examples for facilitating understanding of those skilled in the art, and the description of the embodiments is not intended to limit the present invention. The methyl vinyl silicone rubber raw rubber used in the embodiment of the invention has at least two silicon-bonded alkenyl groups in each molecule, does not contain silicon-bonded hydroxyl groups, and does not contain silicon-bonded alkoxy groups.
Example 1
The components in parts by mass are as follows: 120 parts of methyl vinyl silicone rubber crude rubber with the molar mass of 60 ten thousand g/mol and the vinyl content of 0.16 percent, and the specific area by a BET method of 200m272 parts of fumed silica per gram, 15 parts of diatomite with the particle size of 1 mu m, 1 part of nano cerium oxide with the particle size of 7nm, 3 parts of phenyl silicone oil with the viscosity of 300 centipoises, 8 parts of hydroxy silicone oil with the hydroxy mass fraction of 4% and the viscosity of 28 centipoises, 0.3 part of zinc stearate and 1.2 parts of 2, 4-dichlorobenzoyl peroxide.
The preparation method of the silicone rubber comprises the following steps:
A. adding diatomite into a high-speed stirrer, slowly stirring the mixed powder at the speed of 100r/min, dropwise adding a mixture (the mixing ratio is 1: 2) of vinyltrimethoxysilane and dimethyldimethoxysilane accounting for 1% of the mass of the diatomite, dispersing at the speed of 1000r/min for 30min after dropwise adding is finished, and then sealing and placing for more than 24h to obtain a material I;
B. adding all methyl vinyl silicone rubber crude rubber and partial white carbon black into a kneader, pouring hydroxyl silicone oil and zinc stearate above the white carbon black, stirring and kneading the mixture into a mass at the temperature of between 50 and 80 ℃, adding the rest white carbon black, the material I and the nano cerium oxide in batches, and stirring the mixture to obtain a material II;
C. placing the material II at room temperature for more than 12h, pouring the material II into a kneader, adding phenyl silicone oil, heating to 150-175 ℃, stirring for 1.5-2.5 h, discharging, and cooling to room temperature to obtain a material III;
D. adding 2, 4-dichlorobenzoyl peroxide into the material III, and uniformly stirring to obtain the silicon rubber for the automobile turbo-charging pipe
Example 2
The components in parts by mass are as follows: 110 parts of methyl vinyl silicone rubber crude rubber with the molar mass of 65 ten thousand g/mol and the vinyl content of 0.18 percent, and the specific area by a BET method of 150m280 parts of fumed silica per gram, 10 parts of diatomite with the particle size of 2 mu m, 0 and 5 parts of nano cerium oxide with the particle size of 10nm, 1 part of phenyl silicone oil with the viscosity of 400 centipoises, 5 parts of hydroxy silicone oil with the hydroxy mass fraction of 4 percent and the viscosity of 35 centipoises, 0.2 part of zinc stearate and 0.5 part of 2, 4-dichlorobenzoyl peroxide.
The silicone rubber was prepared in the same manner as in example 1.
Example 3
The components in parts by mass are as follows: 130 parts of methyl vinyl silicone rubber crude rubber with the molar mass of 70 ten thousand g/mol and the vinyl content of 0.2 percent, and the specific area of a BET method is 300m260 parts of fumed silica per gram, 20 parts of diatomite with the particle size of 1 mu m, 2 parts of nano cerium oxide with the particle size of 7nm, 5 parts of phenyl silicone oil with the viscosity of 320 centipoises, 10 parts of hydroxy silicone oil with the hydroxy mass fraction of 4% and the viscosity of 28 centipoises, 0.5 part of zinc stearate and 2 parts of 2, 4-dichlorobenzoyl peroxide.
The silicone rubber was prepared in the same manner as in example 1.
Comparative example 1
The components in parts by mass are as follows: 120 parts of methyl vinyl silicone rubber crude rubber with the molar mass of 60 ten thousand g/mol and the vinyl content of 0.16 percent, and the specific area by a BET method of 200m272 parts of fumed silica per gram, 15 parts of diatomite with the particle size of 1 mu m, 3 parts of phenyl silicone oil with the viscosity of 300 centipoises, 8 parts of hydroxy silicone oil with the hydroxyl mass fraction of 4.0 percent and the viscosity of 28 centipoises, 0.3 part of zinc stearate and 1.2 parts of 2, 4-dichlorobenzoyl peroxide.
The silicone rubber was prepared in the same manner as in example 1.
Comparative example 2
The components in parts by mass are as follows: 110 parts of methyl vinyl silicone rubber crude rubber with the molar mass of 65 ten thousand g/mol and the vinyl content of 0.18 percent, and the specific area by a BET method of 150m280 parts of fumed silica per gram, 10 parts of diatomite with the particle size of 2 mu m, 0 part and 5 parts of nano cerium oxide with the particle size of 10nm, 5 parts of hydroxy silicone oil with the hydroxy mass fraction of 4 percent and the viscosity of 35 centipoises, 0.2 part of zinc stearate and 0.5 part of 2, 4-dichlorobenzoyl peroxide.
The silicone rubber was prepared in the same manner as in example 1.
Comparative example 3
The components in parts by mass are as follows: 130 parts of methyl vinyl silicone rubber crude rubber with the molar mass of 70 ten thousand g/mol and the vinyl content of 0.2 percent, and the specific area of a BET method is 300m260 parts of fumed silica/g, nano-oxidation with particle size of 7nm2 parts of cerium, 5 parts of phenyl silicone oil with the viscosity of 320 centipoises, 10 parts of hydroxyl silicone oil with the hydroxyl mass fraction of 4% and the viscosity of 28 centipoises, 0.5 part of zinc stearate and 2 parts of 2, 4-dichlorobenzoyl peroxide.
The silicone rubber was prepared in the same manner as in example 1.
Testing and analysis
The following performance tests were performed on examples 1 to 5 of the present invention and comparative examples 1 to 3, and the test items and methods were as follows:
hardness test
According to the method "vulcanized rubber or thermoplastic rubber indentation hardness test method part 1" specified in GB/T531.1-2008: shore durometer (shore hardness) ", the hardness of the silicone rubber produced as described above was measured using a shore a durometer model GS-709N.
Tensile Strength and elongation test
The tensile strength and elongation at break of the silicone rubber produced as described above were measured by a KD iii type electronic universal tester according to the method "determination of tensile stress strain properties of vulcanized rubber or thermoplastic rubber" (type I sample) specified in GB/T528-.
Tear Strength test
The tear strength of the silicone rubber produced as described above was measured using a KD III type electronic universal tester according to the method "determination of the tear strength of vulcanized rubber or thermoplastic rubber (trouser, rectangular and crescent test pieces)" specified in GB/T529-.
High temperature resistance test
And (3) placing the 2mm sample piece in a 300 ℃ oven for 24h, taking out the sample piece, placing the sample piece at room temperature for more than 2-3 h, and measuring the hardness, tensile strength, elongation and tearing strength of the sample piece after high-temperature aging according to the physical property test method.
Oil resistance test
ASTM 1 was selected according to the method "liquid resistance test method for vulcanized rubber or thermoplastic rubber" prescribed in GB/T1690-#Mineral oil and ASTM 3#Mineral oil, test conditions 150 ℃/70h to determine the oil resistance of the silicone rubber produced as described above.
Constant compression set performance test
The constant compression set of the silicone rubber produced as described above was determined according to the method "determination of compression set of vulcanized rubber or thermoplastic rubber part 1 of GB/T7759.1-2015, under normal and high temperature conditions, under test conditions of 180 ℃/12h and a compression ratio of 25%.
The test results are shown in table 1: tables of properties of the silicone rubbers obtained in examples 1 to 3 and comparative examples 1 to 3.
TABLE 1
The test results in table 1 show that the silicone rubber for the automobile turbocharger tube prepared in examples 1-3 has tensile strength of more than 10MPa, tear strength of more than 30KN/m, compression set of less than 20%, and good resistance to ASTM 1# mineral oil and ASTM 3# mineral oil, and can meet the use requirements of the silicone rubber material for the automobile turbocharger system on mechanical performance, high temperature resistance, oil resistance and low compression set. When the nano cerium oxide is not added in the comparative example 1, the obtained silicone rubber has poor high temperature resistance and compression set, and cannot meet the use requirements of the silicone rubber material for the automobile turbocharging system on high temperature resistance and low compression set; when the phenyl silicone oil is not added in the comparative example 2, the obtained silicone rubber has poor oil resistance and cannot meet the use requirement of the silicone rubber material for the automobile turbocharging system on oil resistance; when the diatomite is not added in the comparative example 3, the obtained silicone rubber has poor compression set and oil resistance, and cannot meet the use requirements of the silicone rubber material for the automobile turbocharging system on high tensile strength and high tear strength.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (10)
1. The silicone rubber for the automobile turbocharger pipe is characterized by comprising the following components in parts by weight:
100-130 parts of raw methyl vinyl silicone rubber;
60-80 parts of white carbon black;
10-20 parts of diatomite;
0.5-2.0 parts of nano cerium oxide;
1-5 parts of phenyl silicone oil;
5-10 parts of a structural control agent;
0.2-0.5 part of internal release agent;
0.5-2 parts of an organic peroxide vulcanizing agent.
2. The silicone rubber for an automobile turbocharger tube according to claim 1, wherein the raw methyl vinyl silicone rubber has a vinyl content of 0.15-0.2% and a molar mass of 60-70 ten thousand g/mol.
3. The silicone rubber for an automobile turbocharger tube according to claim 1, wherein the diatomaceous earth has a particle size of 1 to 2 μm.
4. The silicone rubber for the automotive turbocharger tube according to claim 1, wherein the structural control agent is a hydroxy silicone oil.
5. The silicone rubber for the automobile turbocharger tube according to claim 4, wherein the hydroxyl silicone oil comprises 3-4% by mass of hydroxyl groups and has a viscosity of 25-35 centipoise.
6. The silicone rubber for an automobile turbocharger tube according to claim 1, wherein the internal mold release agent is one or a mixture of two or more of zinc stearate, stearic acid, and calcium stearate.
7. The silicone rubber for the automobile turbocharger tube according to claim 1, wherein the viscosity of the phenyl silicone oil is 300-400 cps.
8. The method for preparing the silicone rubber for the automobile turbocharger tube according to any one of claims 1 to 7, characterized by comprising the steps of:
A. adding diatomite into a high-speed stirrer, slowly stirring at the speed of 100r/min, dropwise adding a silane coupling agent, dispersing at the high speed of 1000r/min for 30min after dropwise adding, and then sealing and placing for more than 24h to obtain a material I;
B. adding all methyl vinyl silicone rubber crude rubber and partial white carbon black into a kneader, pouring a structural control agent and an internal mold release agent above the white carbon black, heating and kneading into a mass, then respectively adding the rest white carbon black, the material I and the nano cerium oxide, and stirring into a mass to obtain a material II;
C. placing the material II at room temperature for a period of time, then pouring the material II into a kneader, adding phenyl silicone oil, heating and stirring, and then discharging and cooling to obtain a material III;
D. and adding an organic peroxide vulcanizing agent into the material III, and uniformly stirring to obtain the silicone rubber for the automobile turbocharger tube.
9. The preparation method of the silicone rubber for the automobile turbocharger tube according to claim 8, wherein the mass of the part of the white carbon black added for the first time in the step B is 10-30% of the total added white carbon black.
10. The method for preparing silicone rubber for an automotive turbocharger tube according to claim 8, wherein the mixture II in step C is allowed to stand at room temperature for 12 hours or more, heated and stirred at 150 to 175 ℃ for 1.5 to 2.5 hours.
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| CN113122002A (en) * | 2021-05-28 | 2021-07-16 | 瑞源橡塑制品有限公司 | Silica gel used for automobile silicone tube and not adhered to metal at continuous high temperature, preparation method and preparation equipment |
| CN113354949A (en) * | 2021-04-09 | 2021-09-07 | 苏州歌诗夫新材料有限公司 | High-temperature-resistant and illumination-resistant silicon rubber material for sealing household appliance |
| CN113462164A (en) * | 2021-06-25 | 2021-10-01 | 上海珏晟新材料科技有限公司 | High-temperature-resistant silica gel for high-temperature roller and preparation method thereof |
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