Heat-resistant auxiliary agent for silicone rubber and preparation method of heat-resistant auxiliary agent
By introducing surface-modified boehmite functional agents into silicone rubber to form a three-dimensional network structure, the problem of incompatibility between silicone rubber and the matrix is solved, significantly improving the heat resistance and compatibility of silicone rubber and meeting the requirements for use in high-temperature environments.
Patent Information
- Application Number
- CN202511246941.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-02
- Publication Date
- 2025-10-24
AI Technical Summary
Existing heat stabilizers for silicone rubber are incompatible with the matrix, resulting in unsatisfactory modification effects and making it difficult to meet the usage requirements of high-temperature environments such as new energy vehicles, 5G communications, and the photovoltaic industry.
A heat-resistant additive with a surface-modified boehmite functional agent featuring alternating dendritic triphenyl-siloxane blocks is combined with methyl vinyl silicone rubber and vinyl silicone oil to form a three-dimensional network structure. This improves the molecular chain density and compatibility of silicone rubber and utilizes the layered structure of boehmite to block heat transfer.
It significantly improves the heat resistance and compatibility of silicone rubber, forms a physical barrier to prevent the escape of thermal degradation products, and enhances the high-temperature stability of silicone rubber.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of silicone rubber, in particular to a heat-resistant additive for silicone rubber and a preparation method thereof. BACKGROUND
[0002] Silicone rubber is widely used in the fields of electronics and electrical appliances, automobile industry, aerospace and medical treatment due to its unique molecular structure, excellent high and low temperature resistance, electrical insulation, weather resistance and physiological inertia. However, the long-term upper temperature limit of ordinary silicone rubber is only 260 DEG C, which is easy to cause side chain oxidation crosslinking and main chain cyclization depolymerization in the high temperature environment such as engine compartment, battery pack and high temperature sealing, resulting in material hardening, embrittlement and even failure. With the higher requirements of new energy vehicles, 5G communication, photovoltaic industry and other emerging fields on the high temperature resistance of silicone rubber, breaking through the temperature bottleneck of traditional silicone rubber has become the core direction of industry technology research.
[0003] The heat-resistant additive can significantly improve the high temperature stability of silicone rubber by inhibiting the thermal degradation reaction path of silicone rubber. Currently, Fe2O3, MnO2, ZnO, CeO2 and cerium salt, iron salt and other metal salts are commonly used as heat-resistant additives for silicone rubber. This type of heat-resistant additive mainly interrupts the oxidation chain reaction by capturing free radicals, delays the oxidative dehydrogenation process of the methyl group in the side chain of silicone rubber, and improves the heat-resistant stability of silicone rubber. However, this type of heat-resistant stabilizer generally has the problem of incompatibility with the silicone rubber matrix, resulting in unsatisfactory modification effect in practice.
[0004] Therefore, the present application provides a heat-resistant additive for improving the heat-resistant stability of silicone rubber and solving the problems in the prior art. SUMMARY
[0005] (I) Technical problems to be solved In view of the deficiencies of the prior art, the present application provides a heat-resistant additive for silicone rubber and a preparation method thereof.
[0006] (II) Technical solutions A heat-resistant additive for silicone rubber, comprising the following raw materials in parts by weight: Methyl vinyl silicone rubber 75-95 parts; Boehmite functional agent 2-6 parts; Vinyl silicone oil 10-20 parts; Metal catalyst 0.1-0.2 parts; The boehmite functional agent is boehmite with a dendritic structure and a triphenyl-siloxane block alternating connection on the surface.
[0007] As a further scheme of the present application, the preparation method of the boehmite functional agent comprises the following steps: Step one, in the ethanol aqueous solution medium, the boehmite is modified by surface modification using the epoxy silane coupling agent to prepare the boehmite intermediate; Step two, the boehmite intermediate is added into the N,N-dimethylformamide, and is dispersed into a uniform dispersion liquid by ultrasonic dispersion, then the tris-2,6,10-tricarboxylic acid and the phase transfer catalyst are added into the dispersion liquid, after the addition, the stirring is started, the temperature is increased to 60-70 DEG C, and after the temperature is kept for 2-4h, the connecting agent is added, after the addition, the temperature is further increased to 90-100 DEG C, and after the temperature is kept for 9-18h under the condition of continuous stirring, the heating is stopped, the temperature is decreased to discharge, the solid material is separated by centrifugation, and then the washing, vacuum drying treatment are carried out to prepare the boehmite functional agent.
[0008] As a further scheme of the present application, in step one, the epoxy silane coupling agent is selected from 3-glycidyloxypropyltrimethoxysilane or 3-glycidyloxypropyltriethoxysilane.
[0009] As a further scheme of the present application, in step two, the mass ratio of the boehmite intermediate, the tris-2,6,10-tricarboxylic acid and the connecting agent is 1:1.2-2.5:0.5-0.8.
[0010] As a further scheme of the present application, in step two, the phase transfer catalyst is any one of tetrabutylammonium hydrogen sulfate, tetramethylammonium bromide, tetramethylammonium chloride, tetrabutylammonium bromide or tetrabutylammonium chloride.
[0011] As a further scheme of the present application, in step two, the connecting agent is prepared by the following method: The methyldichlorosilane is added into the tetrahydrofuran, and after the stirring to form a uniform reaction liquid, the glycidol and the catalyst are added into the reaction liquid, after the addition, the temperature is adjusted to 60-65 DEG C, and after the stirring and temperature keeping for 2-4h, the solvent is evaporated to collect the product to obtain the connecting agent.
[0012] As a further scheme of the present application, the molar ratio of the methyldichlorosilane and the glycidol is 1:2.
[0013] As a further scheme of the present application, the catalyst is triethylamine or pyridine.
[0014] In the above technical solution, first, the boehmite is surface modified by using an epoxy silane coupling agent to obtain boehmite intermediate material containing epoxy substituents on the surface, then, under the action of a phase transfer catalyst, the epoxy groups of the boehmite intermediate material can undergo ring-opening esterification with the carboxyl substituents in the structure of trisphenyl-2,6,10-tricarboxylic acid, and the remaining active carboxyl groups in the structure can continuously undergo ring-opening addition with the epoxy substituents in the structure of the connecting agent, thereby introducing dendritic structures on the surface of the boehmite, and exhibiting a high molecular material in which trisphenyl-siloxane blocks are alternately connected, i.e., a boehmite functional agent.
[0015] Among them, the connecting agent is prepared by using methyldichlorosilane and glycidol as raw materials, and the Si-Cl groups in the structures of the two react with the hydroxyl substituents, and by controlling the molar ratio of the two, a connecting agent containing two equivalents of epoxy substituents in the structure can be prepared.
[0016] As a further scheme of the present application, the metal catalyst is chloroplatinic acid.
[0017] A preparation method of a heat-resistant aid for silicone rubber, comprising the following steps: In the first step, the raw materials are weighed and matched according to the weight fraction; In the second step, methyl vinyl silicone rubber and vinyl silicone oil are added to a mixing kettle, the temperature is controlled at 40-50℃, and the mixture is uniformly mixed by mechanical stirring at a stirring rate of 500-1000r / min to obtain a premix; In the third step, the boehmite functional agent and the catalyst are added to the premix, the temperature is adjusted to 100-120℃, and the mixture is uniformly stirred at a stirring rate of 200-300r / min, then the heating is stopped, the temperature is lowered, and the mixture is discharged, thereby obtaining the heat-resistant aid.
[0018] (Three) beneficial technical effects The application is prepared by preparing boehmite which is surface modified with dendritic and high molecular material with triphenyl-siloxane block alternating connection, as a functional agent, with methyl vinyl silicone rubber and vinyl silicone oil as raw materials of heat-resistant aid, because Si-H in the structure of high molecular material can carry out silicon hydrogen addition with unsaturated alkenyl in the structure of methyl vinyl silicone rubber and vinyl silicone oil under metal catalysis and high temperature conditions, thus forming a whole type of heat-resistant aid with three-dimensional network structure, on the one hand, the addition of the heat-resistant aid can increase the molecular chain density of silicone rubber, thus hindering the movement of the molecular chain of silicone rubber, and the boehmite exists in the form of crosslinked core, thus greatly improving the compatibility of silicone rubber and boehmite, and further forming physical barrier by using the layered structure of boehmite to prevent heat transfer and the escape of thermal degradation products, thus improving the heat-resistant stability of silicone rubber. DETAILED DESCRIPTION
[0019] In order to facilitate the understanding of the present application, the present application will be described more fully below. The preferred embodiments of the present application are given below. However, the present application can be realized in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided so that the disclosure of the present application can be more thoroughly and completely understood.
[0020] Preparation Example Preparation of boehmite functional agent: Step one, 3.5g boehmite is added to an ethanol aqueous solution medium with a volume fraction of 60%, after ultrasonic dispersion, 1.2g of 3-glycidyl ether oxypropyl triethoxysilane is added, the pH is adjusted to 4, the temperature is increased to 70℃, mechanical stirring is carried out for 6h, then heating is stopped, the temperature is lowered, and the material is discharged, thus preparing boehmite intermediate material; Step two, 1.8g boehmite intermediate material is added to N,N-dimethylformamide, ultrasonic dispersion is carried out to form a uniform dispersion liquid, then 3g of triphenyl-2,6,10-tricarboxylic acid and 0.1g of tetrabutylammonium bromide are added to the dispersion liquid, after addition, stirring is started, the temperature is increased to 65℃, and after 3h of incubation, 1.2g of a coupling agent is added, after the addition is completed, the temperature is further increased to 95℃, and after 16h of incubation under constant stirring, heating is stopped, the temperature is lowered, and the material is discharged, centrifugal separation is carried out to obtain solid material, and then washing, vacuum drying treatment is carried out, thus preparing boehmite functional agent.
[0021] The coupling agent is prepared by the following method: 1.5 g of methyldichlorosilane was added to tetrahydrofuran, stirred until a uniform reaction solution was formed, then 1.9 g of glycidol and triethylamine were added to the reaction solution, after addition, the temperature was adjusted to 65℃, after stirring and keeping for 3 h, the solvent was evaporated to remove, and the product was collected to obtain the linker. Embodiment
[0022] A heat-resistant aid for silicone rubber, comprising the following raw materials in parts by weight: methyl vinyl silicone rubber 75 parts; boehmite functional agent 2 parts; vinyl silicone oil 10 parts; chloroplatinic acid catalyst 0.1 parts; The preparation method of the heat-resistant aid comprises the following steps: Step 1, the raw materials are weighed and matched according to the weight fraction; Step 2, the methyl vinyl silicone rubber and the vinyl silicone oil are added to the mixing kettle, the temperature is controlled at 50℃, and the mixture is uniformly mixed by mechanical stirring at a stirring rate of 800 r / min to obtain a premix; Step 3, the boehmite functional agent and the chloroplatinic acid catalyst are added to the premix, the temperature is adjusted to 120℃, the stirring rate is 300 r / min, after uniform stirring and mixing, the heating is stopped, and the temperature is lowered to discharge, thereby obtaining the heat-resistant aid.
[0023] The preparation method of the boehmite functional agent is shown in the preparation example, and the following are the same. Embodiment
[0024] A heat-resistant aid for silicone rubber, comprising the following raw materials in parts by weight: methyl vinyl silicone rubber 80 parts; boehmite functional agent 5 parts; vinyl silicone oil 12 parts; chloroplatinic acid catalyst 0.1 parts; The preparation method of the heat-resistant aid comprises the following steps: Step 1, the raw materials are weighed and matched according to the weight fraction; Step 2, the methyl vinyl silicone rubber and the vinyl silicone oil are added to the mixing kettle, the temperature is controlled at 50℃, and the mixture is uniformly mixed by mechanical stirring at a stirring rate of 800 r / min to obtain a premix; Step 3, the boehmite functional agent and the chloroplatinic acid catalyst are added to the premix, the temperature is adjusted to 120℃, the stirring rate is 300 r / min, after uniform stirring and mixing, the heating is stopped, and the temperature is lowered to discharge, thereby obtaining the heat-resistant aid. Embodiment
[0025] A heat-resistant additive for silicone rubber, comprising the following raw materials in parts by weight: Methyl vinyl silicone rubber 95 parts; Boehmite functional agent 6 parts; Vinyl silicone oil 20 parts; Chloroplatinic acid catalyst 0.2 parts; The preparation method of the heat-resistant additive, comprising the following steps: Step 1, weigh and mix the raw materials according to the weight ratio; Step 2, add methyl vinyl silicone rubber and vinyl silicone oil to the mixing kettle, control the temperature at 50°C, mechanically stir at a stirring rate of 800 r / min to mix uniformly, and obtain a premix; Step 3, add boehmite functional agent and chloroplatinic acid catalyst to the premix, adjust the temperature to 120°C, and stir at a stirring rate of 300 r / min, then stop heating and cool down to discharge, to obtain the heat-resistant additive.
[0026] Comparative Example 1 A heat-resistant additive for silicone rubber, comprising the following raw materials in parts by weight: Methyl vinyl silicone rubber 80 parts; Boehmite 5 parts; Vinyl silicone oil 12 parts; Chloroplatinic acid catalyst 0.1 parts; The preparation method of the heat-resistant additive, comprising the following steps: Step 1, weigh and mix the raw materials according to the weight ratio; Step 2, add methyl vinyl silicone rubber and vinyl silicone oil to the mixing kettle, control the temperature at 50°C, mechanically stir at a stirring rate of 800 r / min to mix uniformly, and obtain a premix; Step 3, add boehmite and catalyst to the premix, adjust the temperature to 120°C, and stir at a stirring rate of 300 r / min, then stop heating and cool down to discharge, to obtain the heat-resistant additive.
[0027] Comparative Example 2 A heat-resistant additive for silicone rubber, comprising the following raw materials in parts by weight: Methyl vinyl silicone rubber 80 parts; Vinyl silicone oil 12 parts; Chloroplatinic acid catalyst 0.1 parts; The preparation method of the heat-resistant additive, comprising the following steps: Step 1, weigh and mix the raw materials according to the weight ratio; Second step, methyl vinyl silicone rubber and vinyl silicone oil are added into the mixing kettle, the temperature is controlled at 50℃, and the mixture is mechanically stirred at a stirring speed of 800r / min until uniform, to obtain a premix; Third step, the catalyst is added into the premix, the temperature is adjusted to 120℃, and the stirring speed is 300r / min, after uniform stirring, the heating is stopped, and the temperature is lowered to discharge, to obtain the heat-resistant additive.
[0028] Test example 1kg of the heat-resistant additive in the inventive example and the comparative example is respectively weighed, mixed with 10kg of methyl vinyl silicone rubber and 1kg of white carbon black, then 0.5kg of curing agent t-butyl hydroperoxide is added, stirred uniformly, transferred to a mixer, mixed at a temperature of 180℃ for 2h, to prepare each test sample, and the performance test is carried out, and the results are recorded in the following table: Table 1-test results
[0029] Test method: the tensile strength test is tested according to the standard GB / T 528-2009, after the test is completed, the samples of the same batch are placed in an oven at 300℃, and the tensile strength is tested again after heat treatment for 24h, the difference between the tensile strength before and after the calculation is calculated, to evaluate the heat-resistant modification effect of the heat-resistant additive on the silicone rubber.
[0030] According to the analysis of the test results, the heat-resistant additive prepared in the inventive example is used to modify the methyl vinyl silicone rubber, and the sample prepared has excellent heat resistance, and after the boehmite functional agent is replaced by unmodified boehmite, due to the dispersion problem, a stable continuous barrier layer cannot be formed, and a crosslinked network structure cannot be formed, so the heat resistance is greatly reduced.
[0031] In addition, it can be analyzed from the test data that the addition of boehmite has a positive effect on the mechanical properties of silicone rubber.
[0032] The principles and implementations of the present application are described herein with specific examples, and the above description of the embodiments is only used to help understand the method of the present application and its core idea, including the best mode, and also enable any person skilled in the art to practice the present application, including manufacturing and using any device or system, and implementing any combined method. It should be noted that, for those skilled in the art, some improvements and modifications can be made to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application. The scope of patent protection of the present application is defined by the claims, and can include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements similar to the textual expression of the claims, or if they include equivalent structural elements that are not substantially different from the textual expression of the claims, then these other embodiments should also be included in the scope of the claims.
[0033] According to the ideal embodiments of the present application, based on the above description, relevant personnel can make various changes and modifications without deviating from the technical idea of the present application. The technical scope of the present application is not limited to the content of the specification, and must be determined according to the scope of the claims.
Claims
1. A heat-resistant aid for silicone rubber, characterized by, According to the weight parts, the following raw materials are included: Methyl vinyl silicone rubber 75-95 parts; Boehmite functional agent 2-6 parts; Vinyl silicone oil 10-20 parts; Metal catalyst 0.1-0.2 parts; The boehmite functional agent is boehmite with a dendritic surface modified with a high molecular substance exhibiting triphenyl-siloxane block alternating connection.
2. The heat resistant aid for silicone rubber according to claim 1, characterized by, The preparation method of the boehmite functional agent includes the following steps: Step one, in an ethanol aqueous solution medium, the surface of the boehmite is modified with an epoxy silane coupling agent to obtain boehmite intermediate; Step two, the boehmite intermediate is added to N,N-dimethylformamide and ultrasonically dispersed to form a uniform dispersion liquid, then triphenyl-2,6,10-tricarboxylic acid and a phase transfer catalyst are added to the dispersion liquid, after the addition is completed, the stirring is started, the temperature is raised to 60-70℃, and after 2-4h of incubation, a linking agent is added, after the addition is completed, the temperature is further raised to 90-100℃, and after 9-18h of incubation under constant stirring, the heating is stopped, the temperature is lowered, the solid material is centrifuged and separated, and then washed, vacuum dried and treated to obtain the boehmite functional agent.
3. The heat resistant aid for silicone rubber according to claim 2, characterized by In step one, the epoxy silane coupling agent is selected from 3-glycidyloxypropyltrimethoxysilane or 3-glycidyloxypropyltriethoxysilane.
4. The heat resistant aid for silicone rubber according to claim 2, characterized by In step two, the mass ratio of the boehmite intermediate, triphenyl-2,6,10-tricarboxylic acid and linking agent is 1:1.2-2.5:0.5-0.
8.
5. The heat resistant aid for silicone rubber according to claim 2, characterized by In step two, the phase transfer catalyst is any one of tetrabutylammonium hydrogen sulfate, tetramethylammonium bromide, tetramethylammonium chloride, tetrabutylammonium bromide or tetrabutylammonium chloride.
6. The heat resistant aid for silicone rubber according to claim 2, characterized by In step two, the linking agent is prepared by the following method: Methyl dichlorosilane is added to tetrahydrofuran, stirred to form a uniform reaction liquid, then glycidol and a catalyst are added to the reaction liquid, after the addition is completed, the temperature is adjusted to 60-65℃, and after 2-4h of incubation and stirring, the solvent is evaporated to remove, and the product is collected to obtain the linking agent.
7. The heat resistant aid for silicone rubber according to claim 6, characterized by The molar ratio of the methyl dichlorosilane and glycidol is 1:
2.
8. The heat resistant aid for silicone rubber according to claim 6, characterized by, The catalyst is triethylamine or pyridine.
9. The heat resistant aid for silicone rubber according to claim 1, characterized by The metal catalyst is chloroplatinic acid.
10. A process for producing the heat-resistant aid for silicone rubber as claimed in claim 1, characterized by, The following steps are included: First step, each raw material is weighed and matched according to the weight parts; Second step, methyl vinyl silicone rubber and vinyl silicone oil are added to a mixing kettle, the temperature is controlled at 40-50℃, and the pre-mixed material is obtained by mechanical stirring at a stirring rate of 500-1000r / min; Third step, the boehmite functional agent and the catalyst are added to the pre-mixed material, the temperature is adjusted to 100-120℃, the stirring rate is 200-300r / min, after the stirring and mixing are completed, the heating is stopped, the temperature is lowered, and the heat-resistant additive is obtained.