Preparation method of room temperature vulcanized silicone rubber crosslinking agent and application thereof
Patent Information
- Application Number
- CN202610789415.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-03
- Publication Date
- 2026-10-20
AI Technical Summary
[0008]本发明的目的在于提供一种室温硫化硅橡胶交联剂制备方法及其应用，旨在解决上述背景技术中提出的当前室温硫化硅橡胶材料在建筑领域，电子封装领域引用产景日益复杂、功能需求多元化背景下，传统物理增强改性室温硫化硅橡胶的性能存在一定的局限性的问题
[0022]（1）本发明通过环三磷腈衍生物与KH-560之间的环氧开环反应，合成了一种含磷腈和苯环结构单元的新型杂化交联剂HC-PD-KH，反应条件温和，操作简单。
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Abstract
Description
Technical Field
[0001] This invention relates to the technical field of room temperature vulcanizing silicone rubber, and in particular to a method for preparing a room temperature vulcanizing silicone rubber crosslinking agent and its application. Background Technology
[0002] Room temperature vulcanizing silicone rubber is a type of silicone rubber that can cure and crosslink at room temperature by contact with moisture or mixing with a crosslinking agent. Processing does not require special equipment or techniques, and it is suitable for coating and casting molding. Due to its advantages such as simple manufacturing, ease of use, wide variety, and on-site molding capabilities, it is widely used in sealants, adhesives, and on-site molding materials, and has been widely applied in aerospace, construction, automotive, and electronics industries.
[0003] However, traditional room temperature vulcanizing silicone rubber has inherent defects: the main chain of silicone rubber is a -Si-O-Si- structure, with weak intermolecular forces and low cohesive energy, resulting in poor mechanical strength and insufficient thermal stability; moreover, it is easy to melt and drip during combustion and has poor flame retardancy, which limits its high-end applications.
[0004] Existing phosphazene-modified silicone rubber technology only uses phosphazene derivatives as fillers and flame retardants for physical blending. The phosphazene units cannot be chemically bonded into the silicone rubber crosslinking network, resulting in uneven dispersion, poor modification effect, and low performance stability, and failing to achieve molecular-level reinforcement.
[0005] Room temperature vulcanizing silicone rubber can be classified into two types according to its packaging method: single-component and two-component. It can also be classified into two categories according to its vulcanization mechanism: condensation-type and addition-type. Among these, condensation-type room temperature vulcanizing silicone rubber has attracted widespread attention due to its simple processing and low cost.
[0006] However, due to the unique alkyl side chain structure of silicone rubber, the matrix is highly ignitable when exposed to fire, and it drips molten material during combustion, severely limiting its application in fields with high fire resistance requirements, thus restricting the application and development of silicone rubber. Therefore, halogenated flame retardants are commonly used in the market to improve the flame retardant properties of silicone rubber. While these methods are effective, they produce large amounts of smoke after combustion, posing a threat to the environment and human health.
[0007] Phosphazene derivatives have attracted increasing attention due to their unique organic-inorganic hybrid structure. The backbone of these materials consists of alternating phosphorus and nitrogen atoms, surrounded by reactive chlorine atoms, allowing for the introduction of various functional groups through nucleophilic substitution reactions. Phosphazene derivatives have been widely used in the design of reactive flame retardants for epoxy resins, polyolefins, polyamides, polyurethanes, polycarbonates, and polyphenylene ethers. Although studies have reported that phosphazene-containing rigid structures can improve the thermal, mechanical, and flame-retardant properties of silicone rubber, these studies mostly use phosphazene derivatives as fillers, flame retardants, or physical blending additives. In such systems, phosphazene units are typically used as external modifiers rather than chemically bonded to the silicone rubber network. Summary of the Invention
[0008] The purpose of this invention is to provide a method for preparing a crosslinking agent for room temperature vulcanizing silicone rubber and its application, aiming to solve the problem mentioned in the background art that the performance of traditional physically reinforced modified room temperature vulcanizing silicone rubber is limited in the context of increasingly complex application scenarios and diversified functional requirements of current room temperature vulcanizing silicone rubber materials in the fields of construction and electronic packaging.
[0009] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a room temperature vulcanizing silicone rubber crosslinking agent, comprising the following steps:
[0010] (1) Hexachlorocyclotriphosphazene and p-phenylenediamine were dissolved in N,N-dimethylformamide solution, and triethylamine was added. The mixed solution of hexachlorocyclotriphosphazene and p-phenylenediamine was heated to 80°C under magnetic stirring. The mixed solution was stirred and reacted for 8 hours. After the reaction, the solution was cooled to room temperature, the precipitate was collected by centrifugation and washed with ethanol and water. The precipitate was dried under vacuum at 80°C for 24 hours to obtain the phosphazene derivative.
[0011] (2) A two-component mixture was obtained by mixing a phosphazene derivative and 3-glycidyl etheroxypropyltrimethoxysilane. The two-component mixture was reacted at 180°C and 180 rpm for 100 min to obtain a phosphazene silane hybrid silicon-based compound, which is a room temperature vulcanizing silicone rubber crosslinking agent.
[0012] Preferably, the concentration of the N,N-dimethylformamide solution in step (1) is 40 mg / mL to 100 mg / mL.
[0013] Preferably, the molar ratio of hexachlorocyclotriphosphazene to p-phenylenediamine in step (1) is 1:3.
[0014] Preferably, the amount of phosphazene derivative and 3-glycidyl etheroxypropyltrimethoxysilane added in step (2) is 1g and 9g, respectively.
[0015] A method for preparing room temperature vulcanizing silicone rubber includes the following steps:
[0016] The phosphazene silane hybrid silicon-based compound was mixed with an appropriate amount of hydroxyl-terminated polydimethylsiloxane, and a small amount of dibutyltin dilaurate catalyst was added. After stirring for a period of time, the mixture was degassed to prepare room temperature vulcanizing silicone rubber.
[0017] Preferably, the viscosity of the hydroxyl-terminated polydimethylsiloxane is 1000-5000 cp.
[0018] Preferably, the defoaming time is 5-20 minutes.
[0019] Preferably, the stirring speed is 100-2000 rpm and the stirring time is 15 min.
[0020] Preferably, the amount of dibutyltin dilaurate added is 0.1-1g.
[0021] Compared with the prior art, the beneficial effects of the present invention are:
[0022] (1) The present invention synthesizes a novel hybrid crosslinking agent HC-PD-KH containing phosphazene and benzene ring structural units through an epoxy ring-opening reaction between a cyclotriphosphazene derivative and KH-560. The reaction conditions are mild and the operation is simple.
[0023] (2) The room temperature vulcanized silicone rubber prepared by the present invention using HC-PD-KH as a crosslinking agent has a breaking elongation of 200% and a tensile strength of 1.26 MPa as tested by mechanical properties.
[0024] (3) The room temperature vulcanized silicone rubber prepared by the present invention using HC-PD-KH as a crosslinking agent, through thermodynamic performance testing, the temperature corresponding to a 10% mass loss reaches 444.5℃, and after being subjected to a high temperature of 800℃, the mass retention rate reaches 11.4%.
[0025] (4) The preparation conditions of this invention are mild, and the room temperature vulcanized silicone rubber prepared has good mechanical and thermodynamic properties, as well as certain flame retardant properties, providing a new idea for the development of advanced elastomer materials. Attached Figure Description
[0026] Figure 1 The infrared spectrum of the crosslinking agent HC-PD-KH of this invention is shown below.
[0027] Figure 2 These are surface morphology images of the silicone rubber in Examples 5 and 6 of the present invention;
[0028] Figure 3 These are actual images of the silicone rubber used in the mechanical property tests of Examples 1 to 6 of this invention.
[0029] Figure 4These are comparative graphs showing the mechanical properties of silicone rubber tested in Examples 1 to 6 of the present invention.
[0030] Figure 5 This is a comparison chart of the thermodynamic properties of the silicone rubber of this invention and traditional silicone rubber;
[0031] Figure 6 This is a comparison diagram of the dynamic mechanical properties of the silicone rubber of this invention and traditional silicone rubber. Detailed Implementation
[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0033] The dextran and other pharmaceuticals involved in this invention are all commercially available and can be used without purification.
[0034] Example 1
[0035] The preparation of a room temperature vulcanizing silicone rubber crosslinking agent and room temperature vulcanizing silicone rubber includes the following steps:
[0036] (1) Dissolve 3.48 g of hexachlorocyclotriphosphazene and 3.25 g of p-phenylenediamine in 50 ml of N,N-dimethylformamide solution, add 7 ml of triethylamine, heat the mixed solution of hexachlorocyclotriphosphazene and p-phenylenediamine to 80 °C under magnetic stirring, stir the mixed solution for 8 hours, cool the solution to room temperature after reaction, collect the precipitate by centrifugation and wash with ethanol and water, and dry it under vacuum at 80 °C for 24 hours to obtain phosphazene derivative; mix 1 g of phosphazene derivative and 9 g of 3-glycidyl etheroxypropyltrimethoxysilane to obtain a two-component mixture, react the two-component mixture at 180 °C and 180 rpm for 100 min to obtain phosphazene silane hybrid silicon-based compound.
[0037] (2) Weigh 1g of the phosphazene silane hybrid crosslinking agent prepared in (1) above and mix it with 20g of hydroxyl-terminated polydimethylsiloxane. Add 0.5g of dibutyltin dilaurate catalyst, stir for 15min, and then degas to prepare room temperature vulcanizing silicone rubber. The obtained room temperature vulcanizing silicone rubber is denoted as S1.
[0038] Example 2
[0039] The preparation of a room temperature vulcanizing silicone rubber crosslinking agent and room temperature vulcanizing silicone rubber includes the following steps:
[0040] (1) Dissolve 3.48 g of hexachlorocyclotriphosphazene and 3.25 g of p-phenylenediamine in 50 ml of N,N-dimethylformamide solution, add 7 ml of triethylamine, heat the mixed solution of hexachlorocyclotriphosphazene and p-phenylenediamine to 80 °C under magnetic stirring, stir the mixed solution for 8 hours, cool the solution to room temperature after reaction, collect the precipitate by centrifugation and wash with ethanol and water, and dry it under vacuum at 80 °C for 24 hours to obtain phosphazene derivative; mix 1 g of phosphazene derivative and 9 g of 3-glycidyl etheroxypropyltrimethoxysilane to obtain a two-component mixture, react the two-component mixture at 180 °C and 180 rpm for 100 min to obtain phosphazene silane hybrid silicon-based compound.
[0041] (2) Weigh 2g of the phosphazene silane hybrid crosslinking agent prepared in (1) above and mix it with 20g of hydroxyl-terminated polydimethylsiloxane. Add 0.5g of dibutyltin dilaurate catalyst, stir for 15min, and then degas to prepare room temperature vulcanizing silicone rubber. The obtained room temperature vulcanizing silicone rubber is denoted as S2.
[0042] Example 3
[0043] The preparation of a room temperature vulcanizing silicone rubber crosslinking agent and room temperature vulcanizing silicone rubber includes the following steps:
[0044] (1) Dissolve 3.48 g of hexachlorocyclotriphosphazene and 3.25 g of p-phenylenediamine in 50 ml of N,N-dimethylformamide solution, add 7 ml of triethylamine, heat the mixed solution of hexachlorocyclotriphosphazene and p-phenylenediamine to 80 °C under magnetic stirring, stir the mixed solution for 8 hours, cool the solution to room temperature after reaction, collect the precipitate by centrifugation and wash with ethanol and water, and dry it under vacuum at 80 °C for 24 hours to obtain phosphazene derivative; mix 1 g of phosphazene derivative and 9 g of 3-glycidyl etheroxypropyltrimethoxysilane to obtain a two-component mixture, react the two-component mixture at 180 °C and 180 rpm for 100 min to obtain phosphazene silane hybrid silicon-based compound.
[0045] (2) Weigh 3g of the phosphazene silane hybrid crosslinking agent prepared in (1) above and mix it with 20g of hydroxyl-terminated polydimethylsiloxane. Add 0.5g of dibutyltin dilaurate catalyst, stir for 15min, and then degas to prepare room temperature vulcanizing silicone rubber. The obtained room temperature vulcanizing silicone rubber is denoted as S3.
[0046] Example 4
[0047] The preparation of a room temperature vulcanizing silicone rubber crosslinking agent and room temperature vulcanizing silicone rubber includes the following steps:
[0048] (1) Dissolve 3.48 g of hexachlorocyclotriphosphazene and 3.25 g of p-phenylenediamine in 50 ml of N,N-dimethylformamide solution, add 7 ml of triethylamine, heat the mixed solution of hexachlorocyclotriphosphazene and p-phenylenediamine to 80 °C under magnetic stirring, stir the mixed solution for 8 hours, cool the solution to room temperature after reaction, collect the precipitate by centrifugation and wash with ethanol and water, and dry it under vacuum at 80 °C for 24 hours to obtain phosphazene derivative; mix 1 g of phosphazene derivative and 9 g of 3-glycidyl etheroxypropyltrimethoxysilane to obtain a two-component mixture, react the two-component mixture at 180 °C and 180 rpm for 100 min to obtain phosphazene silane hybrid silicon-based compound.
[0049] (2) Weigh 4g of the phosphazene silane hybrid crosslinking agent prepared in (1) above and mix it with 20g of hydroxyl-terminated polydimethylsiloxane. Add 0.5g of dibutyltin dilaurate catalyst, stir for 15min, and then degas to prepare room temperature vulcanizing silicone rubber. The obtained room temperature vulcanizing silicone rubber is denoted as S4.
[0050] Example 5
[0051] The preparation of a room temperature vulcanizing silicone rubber crosslinking agent and room temperature vulcanizing silicone rubber includes the following steps:
[0052] (1) Dissolve 3.48 g of hexachlorocyclotriphosphazene and 3.25 g of p-phenylenediamine in 50 ml of N,N-dimethylformamide solution, add 7 ml of triethylamine, heat the mixed solution of hexachlorocyclotriphosphazene and p-phenylenediamine to 80 °C under magnetic stirring, stir the mixed solution for 8 hours, cool the solution to room temperature after reaction, collect the precipitate by centrifugation and wash with ethanol and water, and dry it under vacuum at 80 °C for 24 hours to obtain phosphazene derivative; mix 1 g of phosphazene derivative and 9 g of 3-glycidyl etheroxypropyltrimethoxysilane to obtain a two-component mixture, react the two-component mixture at 180 °C and 180 rpm for 100 min to obtain phosphazene silane hybrid silicon-based compound.
[0053] (2) Weigh 5g of the phosphazene silane hybrid crosslinking agent prepared in (1) above and mix it with 20g of hydroxyl-terminated polydimethylsiloxane. Add 0.5g of dibutyltin dilaurate catalyst, stir for 15min, and then degas to prepare room temperature vulcanizing silicone rubber. The obtained room temperature vulcanizing silicone rubber is denoted as S5.
[0054] Example 6
[0055] 1g of KH-560 traditional crosslinking agent and 20g of hydroxyl-terminated polydimethylsiloxane were weighed and mixed. 0.5g of dibutyltin dilaurate catalyst was added, and the mixture was stirred for 15 minutes. After degassing, room temperature vulcanizing silicone rubber was prepared. The obtained room temperature vulcanizing silicone rubber is denoted as S0.
[0056] The room temperature vulcanizing silicone rubber prepared in the above examples was characterized and its performance was tested.
[0057] (1) Fourier transform infrared spectroscopy characterization
[0058] The testing instrument used was a Bruker VERTEX 70 Fourier transform infrared spectrometer. An appropriate amount of the HC-PD-KH crosslinking agent powder prepared in Example 1 was ground together with potassium bromide in a mortar, then pressed into a tablet and placed into the Fourier transform infrared spectrometer. The spectrometer was used at room temperature (25°C) at 4000-400 cm⁻¹. -1 FT-IR spectra were acquired within the wavenumber range.
[0059] like Figure 1 The image shown is the infrared spectrum of the crosslinking agent HC-PD-KH in Example 1, at 956 cm⁻¹. -1 The absorption peak at 520 cm⁻¹ corresponds to the vibration of the PNC bond, indicating that PPD has been successfully grafted onto the phosphazene framework. Furthermore, the absorption peak at 520 cm⁻¹ in HCCP... -1 and 600cm -1 The characteristic P–Cl peaks at 3300–3700 cm⁻¹ completely disappear in HC-PD, indicating that the chlorine atoms in HCCP have been almost completely substituted. -1 The presence of a broad absorption peak within the range indicates that the amino group in HC-PD underwent a ring-opening reaction with the epoxy group of KH-560, thereby generating a new hydroxyl (–OH) group. These results preliminarily confirm the successful synthesis of HC-PD-KH.
[0060] (2) Microscopic morphological characterization
[0061] The testing instrument used was a Sigma300 scanning electron microscope from ZEISS, Germany. The silicone rubber prepared by HC-PD-KH was cut into small pieces, sputtered with gold, and then observed and photographed using a scanning electron microscope.
[0062] like Figure 2 The images show the surface morphology of room temperature vulcanizing silicone rubbers prepared with crosslinking agent HC-PD-KH in Examples 6 and 5. It can be seen that the room temperature vulcanizing silicone rubber represented by Example 5 exhibits a large number of protrusions on its surface, making it appear rougher.
[0063] (3) Characterization of mechanical properties
[0064] The instrument used was a CMT6103 universal testing machine from Shenzhen Metersbonwe Co., Ltd. The room temperature vulcanized silicone rubber prepared in Example 3 was cut into 5A dumbbell shapes, and the tensile speed was set to 500 mm / min. During the test, the silicone rubber sample was continuously stretched at a uniform speed until it finally broke.
[0065] Figure 3 The figures show the mechanical property test results of Examples 1 to 6. As can be seen from the figures, the tensile strength and elongation at break of Example 5 reached 1.26 MPa and 200%, respectively, which are significantly improved compared to Example 1.
[0066] (4) Characterization of thermodynamic properties
[0067] Thermogravimetric data were measured using a HIT ACHI STA200 instrument from Beijing Huaxu Century Technology Co., Ltd. A certain amount of sample (5-10 mg, conventional sample, with special element content below 3%, 2-3 mg) was added to an alumina crucible. Under nitrogen protection, the temperature was raised to 30℃, then to 800℃ at a heating rate of 10 K / min, and the weight loss of the sample was recorded.
[0068] Figure 4 The figure shows the thermodynamic properties of Examples 0 (Example 6) to Example 5. It can be seen from the figure that the residual mass of Example 5 after being subjected to a high temperature of 800°C is significantly higher than that of Example 6.
[0069] (5) Characterization of dynamic mechanical properties
[0070] The instrument used was a TA Instruments Q800 from the USA. The viscoelastic properties of the samples were characterized in tensile mode. The rectangular specimens used were 30 mm × 6.5 mm × 3 mm in size. The test temperature range was -130°C to 80°C, the heating rate was set to 10°C / min, and the loading frequency was fixed at 1 Hz.
[0071] Figure 5 These are dynamic mechanical performance diagrams for Examples 0 (Example 6) to 5. It can be seen that the damping performance of Examples 1, 2, 3, 4, and 5 is higher than that of Example 6.
[0072] The above characterization shows that the crosslinking agent prepared by the present invention can produce room temperature vulcanized silicone rubber with strong mechanical properties, stable thermodynamic properties, and good damping ability.
[0073] The phosphazene-silane hybrid crosslinking agent prepared by this invention can directly replace traditional silane crosslinking agents for the industrial production of de-alcoholized room temperature vulcanizing silicone rubber. The product is suitable for building seals, electronic potting, high-temperature gaskets, damping elements, hydrophobic coatings and other fields. The process is compatible with existing production equipment and has significant industrial application value.
[0074] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A method for preparing a room temperature vulcanizing silicone rubber crosslinking agent, characterized in that, Includes the following steps: (1) Hexachlorocyclotriphosphazene and p-phenylenediamine were dissolved in N,N-dimethylformamide solution, and triethylamine was added. The mixed solution of hexachlorocyclotriphosphazene and p-phenylenediamine was heated to 80°C under magnetic stirring. The mixed solution was stirred and reacted for 8 hours. After the reaction, the solution was cooled to room temperature, the precipitate was collected by centrifugation and washed with ethanol and water. The precipitate was dried under vacuum at 80°C for 24 hours to obtain the phosphazene derivative. (2) A two-component mixture was obtained by mixing a phosphazene derivative and 3-glycidyl etheroxypropyltrimethoxysilane. The two-component mixture was reacted at 180°C and 180 rpm for 100 min to obtain a phosphazene silane hybrid silicon-based compound, which is a room temperature vulcanizing silicone rubber crosslinking agent.
2. The method for preparing a room temperature vulcanizing silicone rubber crosslinking agent according to claim 1, characterized in that, The concentration of the N,N-dimethylformamide solution mentioned in step (1) is 40 mg / mL to 100 mg / mL.
3. The method for preparing a room temperature vulcanizing silicone rubber crosslinking agent according to claim 1, characterized in that, The molar ratio of hexachlorocyclotriphosphazene to p-phenylenediamine in step (1) is 1:
3.
4. The method for preparing a room temperature vulcanizing silicone rubber crosslinking agent according to claim 1, characterized in that, The amounts of phosphazene derivative and 3-glycidyl etheroxypropyltrimethoxysilane added in step (2) are 1g and 9g, respectively.
5. A method for preparing room temperature vulcanizing silicone rubber, characterized in that, The room temperature vulcanizing silicone rubber crosslinking agent prepared by any one of the methods described in claims 1-4 includes the following steps: The phosphazene silane hybrid silicon-based compound was mixed with an appropriate amount of hydroxyl-terminated polydimethylsiloxane, and a small amount of dibutyltin dilaurate catalyst was added. After stirring for a period of time, the mixture was degassed to prepare room temperature vulcanized silicone rubber.
6. The method for preparing room temperature vulcanizing silicone rubber according to claim 5, characterized in that, The viscosity of the hydroxyl-terminated polydimethylsiloxane is 1000-5000 cp.
7. The method for preparing room temperature vulcanizing silicone rubber according to claim 5, characterized in that, The defoaming time is 5-20 minutes.
8. The method for preparing room temperature vulcanizing silicone rubber according to claim 5, characterized in that, The stirring speed is 100-2000 rpm, and the stirring time is 15 min.
9. The method for preparing room temperature vulcanizing silicone rubber according to claim 5, characterized in that, The amount of dibutyltin dilaurate added is 0.1-1g.
10. The application of the room temperature vulcanizing silicone rubber crosslinking agent prepared by any one of the methods described in claims 1-4, characterized in that, The crosslinking agent is used as a crosslinking agent for de-alcoholized room temperature vulcanizing silicone rubber. Crosslinking and curing are achieved by reacting the methoxy groups in the crosslinking agent with the terminal hydroxyl groups of the silicone rubber to remove small molecule compounds.