High-temperature-resistant silica gel for gas-phase sample injection port shock insulator as well as preparation method and application of high-temperature-resistant silica gel
By using a vulcanization process with components such as low-phenyl silicone rubber and fumed silica, the problem of silicone rubber being prone to cracking at high temperatures was solved, thus achieving the stability and sealing performance of the gasket at high temperatures.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHEJIANG ORSET TECH CO LTD
- Filing Date
- 2026-01-26
- Publication Date
- 2026-05-12
AI Technical Summary
Traditional silicone gas injection port septa become harder and more prone to cracking after high-temperature baking, making it unable to maintain a normal morphology.
Using low-phenyl silicone rubber as the main raw material, fumed silica, vulcanizing agent, coupling agent, stabilizer and colorant are added. Silicone is prepared through a three-stage vulcanization process. The synergistic effect of hydroxyl silicone oil and cerium oxide is combined to improve the heat resistance and sealing performance of the material.
The prepared gas phase injection port septum is not easily broken at high temperatures, has stable Shore hardness, excellent sealing performance, and can withstand high temperatures of 380-400℃.
Smart Images
Figure CN122011768A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of gas phase injection port septum preparation technology, and in particular to a high-temperature resistant silicone gas phase injection port septum, its preparation method and application. Background Technology
[0002] The injection septum is a key component installed at the injection port of a gas chromatograph. It is usually made of high-temperature resistant and airtight silicone rubber material, which can withstand high temperatures and still maintain good airtightness after multiple injection punctures.
[0003] However, traditional silicone materials have poor high-temperature resistance. Gaskets made from them become harder and more prone to cracking after being baked at high temperatures, and cannot maintain their normal shape.
[0004] Therefore, traditional techniques need to be improved. Summary of the Invention
[0005] The purpose of this invention is to provide a high-temperature resistant silicone gas inlet septum, its application, and a method for preparing the septum, in order to overcome the defects of the gasket prepared above, which becomes harder and more prone to cracking after high-temperature baking and cannot maintain a normal morphology.
[0006] In a first aspect, the present invention provides a high-temperature resistant silicone sealant for a vapor phase injection port septum, the silicone sealant for the vapor phase injection port septum comprising the following components in parts by weight: 100 parts of low-phenyl silicone rubber, 40-60 parts of filler, 0.6-0.8 parts of vulcanizing agent, 1-3 parts of processing aid, 0.5-0.7 parts of coupling agent, 0.5-1 part of stabilizer, and 3-6 parts of colorant; wherein the filler comprises fumed silica; and the processing aid comprises hydroxyl silicone oil.
[0007] Furthermore, the vulcanizing agent includes a diphenyl sulfide.
[0008] Furthermore, the coupling agent includes titanate ester.
[0009] Furthermore, the stabilizer includes cerium oxide.
[0010] Furthermore, the colorant includes inorganic pigments; the inorganic pigments include at least one of iron oxide red, chrome green, and ultramarine blue.
[0011] Furthermore, the content of phenyl groups in the low-phenyl silicone rubber is 5% to 15%.
[0012] Secondly, the present invention provides a method for preparing a high-temperature resistant silicone gas inlet septum, comprising the following steps:
[0013] Weigh each component according to the composition ratio of the high-temperature resistant silica gel for gas phase injection port septum described above.
[0014] The low-phenyl silicone rubber, filler, vulcanizing agent, processing aid, coupling agent, stabilizer, and colorant are mixed to obtain a mixture;
[0015] The mixture is subjected to three vulcanization processes to obtain the target silica gel.
[0016] Furthermore, the step of mixing the low-phenyl silicone rubber, filler, vulcanizing agent, processing aid, coupling agent, stabilizer, and colorant is carried out at a stirring speed of 10 rpm to 20 rpm.
[0017] Furthermore, the three-stage vulcanization process involves first vulcanizing at 20-21 MPa and 180-185°C for 5-8 minutes, then vulcanizing at 0.08-0.09 kPa and 150-155°C for 2-2.5 hours, and finally vulcanizing at 220-230°C for 6-7 hours.
[0018] Thirdly, the present invention provides the application of high-temperature resistant silicone gas phase inlet septum in the preparation of gas phase inlet septums.
[0019] In summary, the technical effects achieved by this invention are:
[0020] Existing vinyl silicone rubber is highly susceptible to thermal decomposition at high temperatures, producing powdery silicone slag. To improve the heat resistance of silicone rubber, the inventors modified its molecular structure by introducing heat-enhancing groups, namely benzene rings, and subsequently used low-phenyl silicone rubber as the main raw material. When silicone rubber is exposed to high temperatures, it generates reactive oxygen species (ROS), such as superoxide radicals (·O₂). 2- Free radicals such as hydroxyl radicals (·OH) attack the Si-O-Si backbone and organic side chains (such as methyl groups) of silica gel, causing molecular chain breakage and resulting in the silica gel turning yellow, becoming sticky, and brittle (i.e., aging). Cerium oxide nanoparticles can quickly capture and neutralize these free radicals, converting them into harmless substances and interrupting the chain reaction that leads to aging.
[0021] Fumed silica has a high specific surface area and porous structure, which can effectively absorb heat and inhibit heat conduction, thus effectively improving the stability of materials under high-temperature environments. Therefore, precipitated silica is no longer used and is replaced entirely by fumed silica.
[0022] Furthermore, the hydroxyl silicone oil in the formula forms cross-linked bonds through a reaction, improving the gasket's resilience and tear resistance. This allows the gasket to maintain good sealing performance even after multiple punctures.
[0023] In summary, the vapor phase gasket prepared from the silicone of the present invention has excellent high-temperature resistance. After high-temperature baking, it does not break, and as the temperature increases, the Shore hardness remains within a reasonable range. It can withstand high temperatures of 380-400℃ and has excellent sealing performance. Attached Figure Description
[0024] Appendix Figure 1 This is a diagram showing the state of the septum in Example 1 after being burned at 380°C for 24 hours.
[0025] Appendix Figure 2 This is a diagram showing the state of the septum in Example 2 after being burned at 380°C for 24 hours.
[0026] Appendix Figure 3 This is a diagram showing the state of the septum in Example 3 after being burned at 380°C for 24 hours.
[0027] Appendix Figure 4 This is a diagram showing the state of the septum in Comparative Example 1 after being burned at 380°C for 24 hours.
[0028] Appendix Figure 5 This is a diagram showing the state of the septum in Comparative Example 2 after being burned at 380°C for 24 hours.
[0029] Appendix Figure 6 This is a diagram showing the state of the septum in Comparative Example 3 after being burned at 380°C for 24 hours. Detailed Implementation
[0030] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention.
[0031] In the prior art, silicone gaskets become harder and more prone to cracking after being baked at high temperatures, making it impossible to maintain their normal shape.
[0032] To overcome the above-mentioned defects, in a first aspect, embodiments of the present invention provide a high-temperature resistant silicone sealant for a vapor phase injection port septum. The silicone sealant for the vapor phase injection port septum comprises the following components in parts by weight: 100 parts of low-phenyl silicone rubber, 40-60 parts of filler, 0.6-0.8 parts of vulcanizing agent, 1-3 parts of processing aid, 0.5-0.7 parts of coupling agent, 0.5-1 part of stabilizer, and 3-6 parts of colorant; wherein the filler includes fumed silica; and the processing aid includes hydroxyl silicone oil.
[0033] In some embodiments, the vulcanizing agent includes a di-2,5-disulfide.
[0034] In some of these embodiments, the coupling agent includes titanate ester.
[0035] In some of these embodiments, the stabilizer includes cerium oxide.
[0036] In some embodiments, the colorant includes inorganic pigments; the inorganic pigments include at least one of iron oxide red, chrome green, and ultramarine blue.
[0037] For example, a high-temperature resistant silicone sealant for a vapor phase injection port comprises the following components in parts by weight: 100 parts of low-phenyl silicone rubber, 40 parts of fumed silica, 0.6 parts of bis(2,5)-pentasulfide, 1 part of hydroxyl silicone oil, 0.5 parts of titanate, 0.5 parts of cerium oxide, and 3 parts of inorganic pigment.
[0038] For example, a high-temperature resistant silicone sealant for a vapor phase injection port septum comprises the following components in parts by weight: 100 parts of low-phenyl silicone rubber, 60 parts of fumed silica, 0.8 parts of bis(2,5-dimethyl)sulfide, 3 parts of hydroxyl silicone oil, 0.7 parts of titanate, 1 part of cerium oxide, and 6 parts of inorganic pigment.
[0039] For example, a high-temperature resistant silicone sealant for a vapor phase injection port septum comprises the following components in parts by weight: 100 parts of low-phenyl silicone rubber, 50 parts of fumed silica, 0.7 parts of bis(2,5)-pentasulfurizing agent, 2 parts of hydroxyl silicone oil, 0.6 parts of titanate, 0.7 parts of cerium oxide, and 4 parts of inorganic pigment.
[0040] In some embodiments, the content of phenyl groups in the low-phenyl silicone rubber is 5% to 15%.
[0041] Secondly, embodiments of the present invention provide a method for preparing a high-temperature resistant silicone gas inlet septum, comprising the following steps:
[0042] Weigh each component according to the component ratio of the high-temperature resistant gas phase injection port septum silica gel;
[0043] The low-phenyl silicone rubber, filler, vulcanizing agent, processing aid, coupling agent, stabilizer, and colorant are mixed to obtain a mixture;
[0044] The mixture is vulcanized three times to obtain the target silica gel.
[0045] In some embodiments, the step of mixing the low-phenyl silicone rubber, filler, vulcanizing agent, processing aid, coupling agent, stabilizer, and colorant is carried out at a stirring speed of 10 rpm to 20 rpm.
[0046] For example, the stirring speed can be specifically selected as a range of values consisting of 10 rpm, 15 rpm, 20 rpm, or any point value, preferably 15 rpm-20 rpm.
[0047] In some embodiments, the three-stage vulcanization process involves first vulcanizing at 20-21 MPa and 180-185°C for 5-8 minutes, then vulcanizing at 0.08-0.09 kPa and 150-155°C for 2-2.5 hours, and finally vulcanizing at 220-230°C for 6-7 hours.
[0048] For example, the three-stage vulcanization process is as follows: first vulcanize at 20 MPa and 185℃ for 8 minutes, then vulcanize at 0.08 kPa and 155℃ for 2.5 hours, and finally vulcanize at 230℃ for 7 hours; or, first vulcanize at 21 MPa and 180℃ for 5 minutes, then vulcanize at 0.09 kPa and 150℃ for 2 hours, and finally vulcanize at 220℃ for 6 hours; or, first vulcanize at 20.5 MPa and 183℃ for 6 minutes, then vulcanize at 0.085 kPa and 153℃ for 2.2 hours, and finally vulcanize at 225℃ for 6.5 hours.
[0049] Thirdly, embodiments of the present invention provide the application of high-temperature resistant silicone gas inlet septum in the preparation of gas inlet septums.
[0050] To better illustrate the technical solution of the present invention, the following specific embodiments are provided. It should be understood that, unless otherwise stated, the raw materials used in the embodiments are all commercially available raw materials.
[0051] Example 1
[0052] A high-temperature resistant silicone sealant for a vapor phase injection port septum comprises the following components in parts by weight: 100 parts low-phenyl silicone rubber, 40 parts fumed silica, 0.6 parts di(2,5-dimethyl)sulfide, 1 part hydroxyl silicone oil, 0.5 parts titanate, 0.7 parts cerium oxide, and 3 parts ultramarine. The low-phenyl rubber contains 5% phenyl groups.
[0053] Example 2
[0054] A high-temperature resistant silicone sealant for a vapor phase injection port septum comprises the following components in parts by weight: 100 parts low-phenyl silicone rubber, 60 parts fumed silica, 0.8 parts di(2,5-dimethyl)sulfide, 3 parts hydroxyl silicone oil, 0.7 parts titanate, 0.5 parts cerium oxide, and 6 parts iron oxide red. The low-phenyl rubber contains 15% phenyl groups.
[0055] Example 3
[0056] A high-temperature resistant silicone sealant for a vapor phase injection port septum comprises the following components in parts by weight: 100 parts low-phenyl silicone rubber, 50 parts fumed silica, 0.7 parts di(2,5-dimethyl)sulfide, 2 parts hydroxyl silicone oil, 0.6 parts titanate, 1 part cerium oxide, and 4 parts chrome green. The low-phenyl rubber contains 10% phenyl groups.
[0057] Comparative Example 1
[0058] In Comparative Example 1, the difference from Example 3 is that the low-phenyl silicone rubber was replaced with an equal amount of vinyl silicone rubber.
[0059] Comparative Example 2
[0060] In Comparative Example 2, the difference from Example 3 is that hydroxyl silicone oil was removed and the weight parts of low-phenyl silicone rubber were increased to 102 parts.
[0061] Comparative Example 3
[0062] A high-temperature resistant silicone sealant for a vapor phase injection port septum comprises the following components in parts by weight: 100 parts vinyl silicone rubber, 40 parts precipitated silica, 10 parts fumed silica, 0.7 parts divinyl chloride, 0.6 parts titanate, and 4 parts ultramarine.
[0063] Performance testing
[0064] I. High-Temperature Baking Test
[0065] Test method: Place the vapor phase septum in a muffle furnace and ignite it at a specified temperature for 24 hours. Test the Shore A hardness before and after ignition according to the requirements of GB / T 531.1-2008.
[0066] See results Figures 1-6 .
[0067] II. Hardness Test at High Temperature
[0068] Before the septum was burned, the hardness of the gas phase septum in Example 1 was tested (GB / T 531.1-2008) to be 50, the hardness of the gas phase septum in Example 2 was 49, and the hardness of the gas phase septum in Example 3 was 50; the hardness of the gas phase septum in Comparative Example 1 was 54, the hardness of the gas phase septum in Comparative Example 2 was 53, and the hardness of the gas phase septum in Comparative Example 3 was 55. After burning at a specific time and temperature, the Shore hardness A of the corresponding gas phase septum was recorded, as shown in Table 1.
[0069] Table 1
[0070] As shown in Table 1:
[0071] 1. In Comparative Example 1, when low-phenyl silicone rubber was replaced with vinyl silicone rubber, it was found that the Shore hardness changed significantly before and after burning. Therefore, using low-phenyl silicone rubber as the raw material can give the gasket better temperature resistance.
[0072] 2. In Comparative Example 2, hydroxyl silicone oil was replaced with low-phenyl silicone rubber, and the amount of low-phenyl silicone rubber was increased. The resulting septum had poor high-temperature resistance. This indicates the synergistic effect of low-phenyl silicone rubber and hydroxyl silicone oil. The combination of the two can greatly improve the high-temperature resistance of the septum.
[0073] 3. The temperature resistance of Comparative Example 3 is not good.
[0074] III. Sealing Test
[0075] Test method: Use a 0.5mm gas phase injection needle to prick the pre-drilled hole on the gas phase septum 50 times, place it at the gas phase injection port, set the gas phase injection port pressure to 300 kPa, and within 1 minute, the pressure drop should not exceed 1 kPa to be considered qualified. The results are shown in Table 2.
[0076] Table 2
[0077] As shown in Table 2, the use of hydroxyl silicone oil in the formulation is more conducive to the gasket maintaining good self-sealing properties after needle insertion, which also proves the synergistic effect of hydroxyl silicone oil and low-phenyl silicone rubber.
[0078] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. The scope of this disclosure is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.
Claims
1. A high-temperature resistant silicone sealant for a gas phase injection port, characterized in that, The silicone septum for the gas phase injection port comprises the following components in parts by weight: 100 parts of low-phenyl silicone rubber, 40-60 parts of filler, 0.6-0.8 parts of vulcanizing agent, 1-3 parts of processing aid, 0.5-0.7 parts of coupling agent, 0.5-1 parts of stabilizer, and 3-6 parts of colorant. The filler includes fumed silica; the processing aid includes hydroxyl silicone oil.
2. The high-temperature resistant silica gel for a gas phase injection port septum according to claim 1, characterized in that, The vulcanizing agent includes a di-25 vulcanizing agent.
3. The high-temperature resistant silicone gas inlet septum according to claim 1, characterized in that, The coupling agent includes titanate.
4. The high-temperature resistant silica gel for a gas phase injection port septum according to claim 1, characterized in that, The stabilizer includes cerium oxide.
5. The high-temperature resistant silicone gas inlet septum according to claim 1, characterized in that, The colorant includes inorganic pigments; the inorganic pigments include at least one of iron oxide red, chrome green, and ultramarine blue.
6. A high-temperature resistant silica gel for a gas phase injection port septum according to any one of claims 1 to 5, characterized in that, The content of phenyl groups in the low-phenyl silicone rubber is 5% to 15%.
7. A method for preparing a high-temperature resistant silica gel septum for a gas phase injection port, characterized in that, The process includes the following: Weigh each component according to the component ratio of the high-temperature resistant silica gel for gas phase injection port septum according to any one of claims 1 to 6; The low-phenyl silicone rubber, filler, vulcanizing agent, processing aid, coupling agent, stabilizer, and colorant are mixed to obtain a mixture; The mixture is subjected to three vulcanization processes to obtain the target silica gel.
8. The method for preparing a high-temperature resistant silica gel for a gas phase injection port septum according to claim 7, characterized in that, The step of mixing the low-phenyl silicone rubber, filler, vulcanizing agent, processing aid, coupling agent, stabilizer, and colorant is carried out at a stirring speed of 10 rpm to 20 rpm.
9. A method for preparing a high-temperature resistant silica gel septum for a gas phase injection port according to claim 7, characterized in that, The three-stage vulcanization process involves first vulcanizing at 20-21 MPa and 180-185°C for 5-8 minutes, then vulcanizing at 0.08-0.09 kPa and 150-155°C for 2-2.5 hours, and finally vulcanizing at 220-230°C for 6-7 hours.
10. The application of the high-temperature resistant silica gel for gas phase inlet septum as described in any one of claims 1 to 6 in the preparation of gas phase inlet septums.