A high-barrier butyl rubber septum material for preventing volatile cross-contamination and a method for preparing the same

Abstract

The application belongs to the field of high polymer materials, and discloses a volatile-preventing and string-preventing high-barrier butyl rubber septum material and a preparation method thereof. The material comprises, by weight, butyl rubber 90-110 parts, modified sheet layer filler 5-12 parts, silane coupling agent containing dynamic bond 2-5 parts, polyisobutylene core-fluorine-containing hydrophobic shell core-shell microsphere 1-3 parts, vulcanizing agent 1.5-3 parts, vulcanization accelerator 0.8-2 parts, and activator 3-5 parts. By constructing a triple synergistic structure of "sheet layer directional barrier-dynamic interface plugging-matrix hydrophobic network interception", the penetration and stringing of volatile organic components in the sealing system are effectively inhibited. The preparation method comprises the steps of sheet layer filler modification, rubber matrix mixing, dynamic vulcanization and post-molding vulcanization, and has high controllability. The prepared material has excellent gas barrier property, puncture resistance and low-temperature elasticity, and is suitable for chromatographic sample bottle sealing systems.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials, specifically relating to a high-barrier butyl rubber septum material that prevents volatile cross-contamination and its preparation method. Background Technology

[0002] In chromatographic analysis, sample pretreatment, and automated sample introduction systems, the vial septum serves as a critical sealing component, primarily used to maintain sample sealing under repeated puncture conditions, preventing leakage or migration of volatile components. Especially in trace analysis and high-throughput detection scenarios, organic solvents or volatile compounds in the sample can permeate and diffuse during storage and injection, easily leading to cross-contamination between adjacent samples, thus affecting the accuracy and repeatability of the detection results.

[0003] Currently, septum materials mostly use silicone rubber or butyl rubber systems. Butyl rubber, due to its dense molecular chain and low gas permeability, is widely used in the field of sealing materials. In existing technologies, such as the published patent CN121249059A, a butyl rubber sealing material is provided, which improves the material's aging resistance and mechanical properties through formulation optimization and co-vulcanization processes. However, its technical focus is mainly on the durability of the seal, with insufficient attention paid to the barrier effect of volatile components during multi-stage permeation. On the other hand, patent CN113733689B improves the gas barrier performance of brominated butyl rubber materials by constructing alternating layered structures. However, this approach mainly relies on a single layered structure to extend the diffusion path, making it difficult to balance high barrier performance with the high elasticity and low-temperature resilience required by rubber materials. In practical applications, simply increasing the filler content or introducing hydrophobic additives to enhance barrier performance often leads to decreased material elasticity and poorer puncture recovery. Furthermore, traditional hydrophobic additives also have the problem of migration and precipitation, which can interfere with analytical results. Summary of the Invention

[0004] To address the shortcomings mentioned in the background art, the present invention aims to provide a high-barrier butyl rubber septum material and its preparation method for preventing volatile cross-contamination. It constructs a synergistic structure of "directional sheet barrier – dynamic interface blocking – hydrophobic network interception" to effectively block the entire process of dissolution, diffusion and penetration of volatile components in the sample. It has both high barrier properties and excellent elasticity and is suitable for chromatographic sample injection sealing systems.

[0005] The objective of this invention can be achieved through the following technical solutions: A high-barrier butyl rubber septum material for preventing volatile cross-contamination comprises the following raw materials in parts by weight: 90-110 parts butyl rubber, 5-12 parts oriented lamellar filler, 2-5 parts silane coupling agent containing dynamic bonds, 1-3 parts polyisobutylene core-fluorinated hydrophobic core-shell microspheres, 1.5-3 parts vulcanizing agent, 0.8-2 parts vulcanization accelerator, and 3-5 parts activator.

[0006] More preferably, the directional sheet filler is selected from one or more of organically modified montmorillonite, hydrophobically modified graphene, organically modified attapulgite, hydrophobically modified vermiculite, and organically modified bentonite.

[0007] More preferably, the Mooney viscosity ML(1+8)100 °C of the butyl rubber is 45-60; when the oriented sheet filler is organically modified montmorillonite, its interlayer spacing is 2.5-4.0 nm; when the oriented sheet filler is hydrophobically modified graphene, its aspect ratio is not less than 300.

[0008] More preferably, the silane coupling agent containing dynamic bonds is 5-(1,2-dithioalkyl-3-yl)-N-[3-(triethoxysilyl)propyl]pentanamide.

[0009] More preferably, the synthesis method of the silane coupling agent containing dynamic bonds includes the following steps: under nitrogen protection, thioctic acid and aminopropyltriethoxysilane are added to the organic solvent N,N-dimethylformamide in a molar ratio of 1:1.05 to 1:1.1, and 4-dimethylaminopyridine is added as a catalyst at a mass ratio of 2% to 3% relative to the total mass of the reactants. After the reaction is completed, the mixture is purified by vacuum distillation to obtain the silane coupling agent containing dynamic bonds.

[0010] More preferably, in the polyisobutylene core-fluorinated hydrophobic core-shell microspheres, the core layer is polyisobutylene, and the shell layer is selected from polyvinylidene fluoride or polychlorotrifluoroethylene; the particle size of the core-shell structure microspheres is 50-200 nm, and the mass ratio of the core layer to the shell layer is 3:1-5:1.

[0011] More preferably, the vulcanizing agent is sulfur; the vulcanization accelerator is selected from one or more of thiuram accelerators and dithiocarbamate accelerators, wherein the thiuram accelerators include TMTD, TMTM, and TETD, and the dithiocarbamate accelerators include ZDBC, ZDMC, and ZDEC; the activator is a mixture of zinc oxide and stearic acid, wherein the mass ratio of zinc oxide to stearic acid is 3:1 to 4:1.

[0012] A method for preparing a high-barrier butyl rubber septum material that prevents volatile cross-contamination includes the following steps: S1. Add the oriented sheet packing to the mixing equipment, then add the silane coupling agent containing dynamic bonds, and mix and stir to obtain the modified sheet packing; S2. Add butyl rubber to the plasticizing equipment for plasticizing, and then add modified lamellar filler, polyisobutylene core-fluorinated hydrophobic core-shell microspheres, and activator in sequence, and continue to mix to form a rubber blend; S3. Add vulcanizing agent and vulcanization accelerator to rubber blend, mix and under shearing action to make the oriented lamellar filler be oriented; S4. The mixed rubber compound is placed into a molding equipment for molding and vulcanization. After molding and vulcanization, post-vulcanization treatment is performed. After cooling to room temperature, it is cut to obtain the butyl rubber diaphragm material.

[0013] More preferably, in step S1, the mixing temperature is 80-90℃, the mixing time is 30-40 min, and the mixing speed is 1500-2000 r / min; in step S2, the plasticizing temperature is 100-110℃, the plasticizing time is 5-8 min, the mixing time is 10-15 min, the internal mixer rotor speed is 40-60 r / min, and the filling coefficient is 0.6-0.7.

[0014] More preferably, in step S3, the mixing temperature is 120–130°C, the mixing time is 8–12 min, and the shear rate is 500–800 s⁻¹; in step S4, the molding vulcanization temperature is 150–160°C, the molding vulcanization pressure is 15–20 MPa, the molding vulcanization time is 15–20 min, the post-vulcanization temperature is 100–110°C, and the post-vulcanization time is 4–6 h.

[0015] The beneficial effects of this invention are: This invention achieves highly efficient barrier protection for volatile components throughout the entire process of "dissolution-diffusion-permeation" by constructing a triple coupling mechanism of "layered directional physical barrier – dynamic interface hydrophobic sealing – matrix hydrophobic network interception," effectively solving the problem of existing septum materials struggling to balance high barrier protection and high elasticity. The layered filler achieves a regular orientation through shear induction, forming an efficient diffusion path delay barrier within the rubber, effectively extending the permeation path. A customized silane coupling agent containing dynamic bonds endows the filler with good interfacial compatibility and self-adaptive sealing capabilities, significantly improving interfacial continuity and airtightness, and mitigating the risk of localized leakage caused by layer agglomeration. The introduction of a polyisobutylene elastic core – fluorinated hydrophobic core-shell microspheres – replaces the traditional hydrophobic wax crystal structure. The microsphere shell is highly hydrophobic, effectively intercepting residual molecules not blocked by the layered and interfacial structures. The elastic core layer forms an interpenetrating network structure with the butyl rubber matrix, maintaining excellent low-temperature elasticity and puncture recovery while significantly reducing the performance degradation caused by the migration and precipitation of hydrophobic additives. Attached Figure Description

[0016] The invention will now be further described with reference to the accompanying drawings.

[0017] Figure 1This is a comparison chart of the water vapor transmission rate and volatile component transmission rate of the high-barrier butyl rubber septum materials prepared in the embodiments and comparative examples of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0019] Example 1: I. Preparation of silane coupling agents containing dynamic bonds In a nitrogen-protected 500 mL three-necked flask, 28.6 g of lipoic acid and 200 mL of N,N-dimethylformamide were added. Mechanical stirring was started, and the temperature was raised to 50 °C to completely dissolve the lipoic acid. Nitrogen gas was continuously introduced, and 39.2 g of aminopropyltriethoxysilane was slowly added dropwise at a ratio of 1:1.08 (lipoic acid to aminopropyltriethoxysilane), with a dropping rate controlled at 1 drop / second. The system temperature was maintained at 50-55 °C during the addition. After the addition was complete, stirring was continued for 15 min. 1.36 g of 4-dimethylaminopyridine was added as a catalyst, and the temperature was raised to 60 °C. The reaction was maintained at this temperature for 4 h under nitrogen protection. After the reaction was completed, the system was cooled to room temperature and then distilled under reduced pressure at a vacuum of 0.08 MPa and a temperature of 75-80 °C to remove the solvent N,N-dimethylformamide and excess aminopropyltriethoxysilane, yielding a pale yellow viscous liquid product, which is the silane coupling agent 5-(1,2-dithioalkyl-3-yl)-N-[3-(triethoxysilyl)propyl]pentanamide containing dynamic bonds.

[0020] II. Preparation of polyisobutylene core-fluorinated hydrophobic core-shell microspheres Add 1.2 g of sodium dodecyl sulfate and 0.3 g of n-pentanol to 200 mL of deionized water, stir at 300 r / min for 10 min, heat to 70 ℃, and purge with nitrogen for 30 min to remove oxygen. Dissolve 8 g of polyisobutylene with a number average molecular weight of 10000 in 20 mL of anhydrous ethanol, stir well, and add it dropwise to the above emulsion system at a rate of 1 drop / second. After the addition is complete, keep the mixture at 70 ℃ and stir for 1 h. Then add 0.2 g of ammonium persulfate and stir for 15 min to initiate a free radical polymerization reaction.

[0021] 2 g of tridecafluorooctyl methacrylate, 0.5 g of butyl acrylate, and 10 mL of anhydrous ethanol were mixed thoroughly and slowly added dropwise to the seed emulsion. The system temperature was maintained at 70-75 °C and the stirring rate at 300 r / min. After the addition was complete, the mixture was kept at a constant temperature for 3 h to complete the shell coating. After the reaction was completed, the mixture was cooled to room temperature, and the pH of the system was adjusted to 7.0 with 0.1 mol / L sodium hydroxide solution. The mixture was centrifuged at 8000 r / min for 20 min, and the precipitate was collected and washed three times alternately with deionized water and anhydrous ethanol to remove residual monomers and emulsifiers. The precipitate was dried in a vacuum drying oven at 60 °C for 12 h to obtain the polyisobutylene core-fluorinated hydrophobic core-shell microspheres.

[0022] III. Preparation of High-Barrier Butyl Rubber Septum Material to Prevent Volatile Cross-Contamination The high-barrier butyl rubber septum material for preventing volatile cross-contamination comprises the following raw materials in parts by weight: 90 parts butyl rubber, 5 parts oriented lamellar filler, 2 parts silane coupling agent containing dynamic bonds, 1 part polyisobutylene core-fluorinated hydrophobic core-shell microspheres, 1.5 parts vulcanizing agent, 0.8 parts vulcanization accelerator, and 3 parts activator.

[0023] The preparation steps of the high-barrier butyl rubber septum material that prevents cross-contamination are as follows: S1. Disperse 50 g of natural sodium-based montmorillonite in 500 mL of deionized water and heat to 60 ℃. Slowly add 2.5 g of dodecyltrimethylammonium bromide and stir for 2 h. After reaction, allow to stand to precipitate, wash until neutral, and vacuum dry at 60 ℃ for 12 h to obtain organically modified montmorillonite with an interlayer spacing of approximately 2.8 nm. Add 50 g of organically modified montmorillonite and 20 g of silane coupling agent containing dynamic bonds to a high-speed mixer and stir at 1500 r / min for 30 min at 80 ℃ under nitrogen protection to obtain modified sheet filler.

[0024] S2. Add 900 g of butyl rubber to a mixer and plasticize at 100 °C for 5 min. Then add 70 g of the modified lamellar filler obtained in step S1, 10 g of polyisobutylene core-fluorinated hydrophobic shell microspheres, and 30 g of activator (zinc oxide and stearic acid), and continue mixing for 10 min. The mixing rotor speed is 40 r / min, and the filling factor is 0.6 to obtain a uniformly dispersed rubber blend.

[0025] S3. Add 15 g of sulfur and 8 g of TMTD to the blend from step S2, and continue mixing for 8 min at a mixing temperature of 120℃. During the mixing process, the shear-induced modified lamellar filler is directionally distributed in the rubber matrix, achieving integrated dynamic vulcanization and structure guidance.

[0026] S4. The mixed rubber compound is placed in a molding machine and hot-pressed for 15 minutes at 150 ℃ and 15 MPa. After curing, the product is placed in an oven and post-cured at 100 ℃ for 4 hours, then slowly cooled to room temperature to obtain the butyl rubber diaphragm material.

[0027] Example 2: The preparation methods of the silane coupling agent containing dynamic bonds and the polyisobutylene core-fluorinated hydrophobic core-shell microspheres are the same as those in Example 1.

[0028] The high-barrier butyl rubber septum material for preventing volatile cross-contamination comprises the following raw materials in parts by weight: 110 parts butyl rubber, 12 parts oriented lamellar filler, 5 parts silane coupling agent containing dynamic bonds, 3 parts polyisobutylene core-fluorinated hydrophobic core-shell microspheres, 3 parts vulcanizing agent, 2 parts vulcanization accelerator, and 5 parts activator.

[0029] The preparation steps of the high-barrier butyl rubber septum material that prevents cross-contamination are as follows: S1. Prepare organically modified montmorillonite according to the method of Example 1. Add 120 g of dried organically modified montmorillonite and 50 g of silane coupling agent containing dynamic bonds to a high-speed mixer. Stir for 30 min at 80 °C and 1500 r / min under nitrogen protection to obtain modified sheet filler after full grafting reaction.

[0030] S2. 1100 g of butyl rubber was put into an open plasticizer and plasticized at 110 °C for 8 min. Then, 120 g of the modified lamellar filler prepared in step S1, 30 g of polyisobutylene core-fluorinated hydrophobic core-shell microspheres (particle size 200 nm, core-shell mass ratio 5:1), 40 g of zinc oxide and 10 g of stearic acid (mass ratio 4:1) were added in sequence. The mixture was continued to be mixed for 15 min. The rotor speed of the internal mixer was 60 r / min and the filling coefficient was controlled at 0.7 to obtain a uniformly dispersed rubber blend.

[0031] S3. Add 30 g of sulfur as a vulcanizing agent to the above rubber blend, and add a total of 20 g of composite vulcanization accelerator, wherein TMTD, TETD and ZDBC are equally distributed by mass, and continue to mix at 130 ℃ for 12 min.

[0032] S4. After the mixed and vulcanized rubber compound is pressed into sheets, it is fed into a flat vulcanizing machine. The vulcanization temperature is set to 160 ℃, the pressure to 20 MPa, and the holding time to 20 min to complete the molding vulcanization. Immediately after demolding, the semi-finished product is placed in a forced-air drying oven and subjected to post-vulcanization treatment at 110 ℃ for 6 h. After the post-vulcanization is completed, it is naturally cooled to room temperature to obtain the butyl rubber gasket material.

[0033] Example 3: The preparation methods of the silane coupling agent containing dynamic bonds and the polyisobutylene core-fluorinated hydrophobic core-shell microspheres are the same as those in Example 1.

[0034] The high-barrier butyl rubber septum material for preventing volatile cross-contamination comprises the following raw materials in parts by weight: 100 parts butyl rubber, 9 parts oriented lamellar filler, 3.5 parts silane coupling agent containing dynamic bonds, 2 parts polyisobutylene core-fluorinated hydrophobic core-shell microspheres, 2.25 parts vulcanizing agent, 1.2 parts vulcanization accelerator, and 3.5 parts activator.

[0035] The preparation steps of the high-barrier butyl rubber septum material that prevents cross-contamination are as follows: S1. Prepare organically modified montmorillonite according to the method of Example 1. Add 90 g of dried organically modified montmorillonite and 35 g of silane coupling agent containing dynamic bonds into a high-speed mixer, and stir at 1500 r / min for 30 min at 80 °C under nitrogen protection to obtain surface-grafted modified lamellar filler.

[0036] S2. Add 1000 g of butyl rubber to a two-roll mill and plasticize at 107 °C for 7 min. Then add 90 g of the modified lamellar filler prepared in step S1, 20 g of polyisobutylene core-fluorinated hydrophobic core-shell microspheres (particle size about 125 nm, core-shell mass ratio of 4:1), and 35 g of activator (zinc oxide to stearic acid mass ratio of 3.5:1). Mix evenly for 13 min, with the internal mixer rotor speed at 50 r / min and the filling factor controlled at 0.65 to obtain a rubber blend.

[0037] S3. Add 22.5 g of sulfur as a vulcanizing agent to the above rubber blend, and add 12 g of composite accelerator, wherein TMTD, TMTM, and ZDBC are mixed in a mass ratio of 1:1:1, the mixing temperature is controlled at 127 ℃, and the mixing time is 10 min.

[0038] S4. After the mixed rubber compound is pressed into sheets using a two-roller sheeter, it is placed in a flat vulcanizing machine for molding and vulcanization. The parameters are set as follows: vulcanization temperature 157 ℃, pressure 18 MPa, and vulcanization time 18 min. After molding, the semi-finished product is demolded and placed in a hot air circulating oven for post-vulcanization treatment at a temperature of 105 ℃ for 5 h. After treatment, it is naturally cooled to room temperature to obtain the butyl rubber gasket material.

[0039] Comparative Example 1: The preparation method of the polyisobutylene core-fluorinated hydrophobic core-shell microspheres is the same as that in Example 1.

[0040] The high-barrier butyl rubber septum material for preventing volatile cross-contamination comprises the following raw materials in parts by weight: 100 parts butyl rubber, 9 parts oriented sheet filler, 2 parts polyisobutylene core-fluorinated hydrophobic core-shell microspheres, 2.25 parts vulcanizing agent, 1.2 parts vulcanization accelerator, and 3.5 parts activator.

[0041] The preparation steps of the high-barrier butyl rubber septum material that prevents cross-contamination are as follows: S1. Organically modified montmorillonite was prepared according to the method of Example 1, without grafting treatment with silane coupling agent, and was denoted as untreated sheet filler.

[0042] S2. Add 1000 g of butyl rubber to a two-roll mill and plasticize at 107 °C for 7 min. Then add 90 g of untreated lamellar filler, 20 g of polyisobutylene core-fluorinated hydrophobic core-shell microspheres (particle size approximately 125 nm, core-shell mass ratio 4:1), and 35 g of activator (zinc oxide to stearic acid mass ratio 3.5:1). Mix thoroughly for 13 min at a speed of 50 r / min on the internal mixer rotor and a filling factor of 0.65 to obtain a rubber blend.

[0043] S3. Add 22.5 g of sulfur and 12 g of accelerator (TMTD, TMTM, and ZDBC are mixed in a mass ratio of 1:1:1) to the above rubber blend. The mixing temperature is controlled at 127 °C and the mixing time is 10 min.

[0044] S4. After the mixed rubber compound is pressed into sheets using a two-roller sheeter, it is placed in a flat vulcanizing machine for molding and vulcanization. The parameters are set as follows: vulcanization temperature 157 ℃, pressure 18 MPa, and vulcanization time 18 min. After molding, the material is demolded and then subjected to post-vulcanization treatment by heating in a 105 ℃ hot air circulating oven for 5 h. After treatment, it is naturally cooled to room temperature to obtain the butyl rubber gasket material.

[0045] Comparative Example 2: The preparation method of the silane coupling agent containing dynamic bonds is the same as that in Example 1.

[0046] The high-barrier butyl rubber septum material for preventing volatile cross-contamination comprises the following raw materials in parts by weight: 100 parts butyl rubber, 9 parts oriented lamellar filler, 3.5 parts silane coupling agent containing dynamic bonds, 2.25 parts vulcanizing agent, 1.2 parts vulcanization accelerator, and 3.5 parts activator.

[0047] The preparation steps of the high-barrier butyl rubber septum material that prevents cross-contamination are as follows: S1. Prepare organically modified montmorillonite according to the method of Example 1. Add 90 g of dried organically modified montmorillonite and 35 g of silane coupling agent containing dynamic bonds into a high-speed mixer, and stir at 1500 r / min for 30 min at 80 °C under nitrogen protection to obtain surface-grafted modified lamellar filler.

[0048] S2. Plasticize 1000 g of butyl rubber at 107 °C for 7 min. Then add 90 g of modified lamellar filler and 35 g of activator (zinc oxide to stearic acid mass ratio of 3.5:1) in sequence, and continue to mix for 13 min. The rotor speed is 50 r / min, and the filling factor is controlled at 0.65 to obtain a rubber blend without core-shell microspheres.

[0049] S3. Add 22.5 g of sulfur to the above rubber blend, and at the same time add 12 g of accelerator (TMTD, TMTM, and ZDBC are mixed in a mass ratio of 1:1:1), and mix at 127 °C for 10 min.

[0050] S4. After the mixed rubber compound is pressed into sheets, it is placed in a flat vulcanizing machine. The molding and vulcanizing temperature is set to 157 ℃, the pressure to 18 MPa, and the time to 18 min. After vulcanization, the material is demolded and placed in a 105 ℃ hot air circulating oven for post-vulcanization treatment for 5 h. After treatment, it is naturally cooled to room temperature to obtain the butyl rubber gasket material.

[0051] Performance testing: 1. Water vapor transmission rate test According to GB / T 1037 standard, the sample is cut into a circular piece with a thickness of 2 mm, fixed on a moisture permeation cup, and placed under the conditions of 38 ℃ and 90% relative humidity. The water vapor permeability of the material is calculated by the change in water vapor mass per unit time, which is used to evaluate the overall blocking ability of the material against small molecule gases and water vapor.

[0052] 2. Permeability test of volatile components A simulated permeation experiment was conducted. The septum material was placed in a closed double-chamber device. A certain amount of a mixed volatile solvent of ethanol and n-hexane was added to one side, while the other side was a blank collection chamber. The area of ​​the test sample was fixed at 10 cm². The device was placed at 40 °C for 72 h. The cumulative permeation of volatile components in the collection chamber was detected by gas chromatography-mass spectrometry to characterize the septum material's ability to block volatile organic molecules and prevent cross-contamination.

[0053] 3. Compression set test The compression set test was conducted according to GB / T 7759 standard. The sample was kept in an environment of 70 ℃ for 24 h under 25% compression deformation, unloaded and recovered at room temperature for 30 min, and its thickness change was measured. The compression set was calculated to evaluate the deformation recovery ability of the material under sealed conditions and the long-term sealing reliability.

[0054] 4. Low-temperature elasticity retention test The sample was placed in an environment of −20 °C and left to stand for 24 h. Then, the rebound rate was tested at this temperature and compared with the rebound rate at room temperature. The low-temperature elasticity retention rate was calculated to evaluate the degree of elasticity decay of the material under low-temperature conditions.

[0055] 5. Surface hydrophobicity test The surface hydrophobicity was characterized by a static water droplet contact angle test. A 5 μL deionized water droplet was added to the sample surface, and the angle between the water droplet and the material surface was measured using a contact angle meter to reflect the hydrophobic properties of the material surface and interface structure.

[0056] The test results are shown in Table 1 below.

[0057] Table 1 Performance test results of various butyl rubber diaphragm material samples

[0058] As shown in Table 1, the sample of the example is superior to the comparative example in terms of barrier performance, deformation recovery ability, low temperature adaptability and interface hydrophobicity. Among them, Example 2 has the most outstanding performance in multiple performance tests.

[0059] Based on the water vapor permeability results, the permeability of Examples 1–3 were 4.1, 2.7, and 3.3 g·m⁻²·d⁻¹, respectively, all significantly lower than that of Comparative Example 1 (6.8 g·m⁻²·d⁻¹) and Comparative Example 2 (5.7 g·m⁻²·d⁻¹). Among them, Example 2 showed the best performance, which is attributed to the synergistic construction of a complete barrier channel by the core-shell microspheres, oriented sheets, and silane coupling agent, significantly extending the water vapor diffusion path and demonstrating the strong inhibitory ability of this invention against micro-molecule permeation.

[0060] Regarding the permeation of volatile components, Example 2 showed a permeation of only 38 μg / 72 h, which is much lower than that of Comparative Example 1 (96 μg / 72 h) and Comparative Example 2 (89 μg / 72 h). This result indicates that the hydrophobic interface and dense network structure constructed in the material can effectively prevent the "dissolution-diffusion-penetration" process of volatile organic components, significantly improving the shielding ability of the sample against volatile organic compounds. It is suitable for airtight sealing scenarios with extremely high requirements for cross-contamination control.

[0061] In the compression set test, the deformation rates of the sample samples in the examples were all between 24% and 28%, which were significantly better than those of Comparative Example 1 (35%) and Comparative Example 2 (38%), indicating that the material has good recovery performance and shape stability under long-term sealed compression conditions. This is due to the interpenetrating network structure formed by the polyisobutylene elastic core in the rubber matrix, which improves the overall elasticity without destroying the cross-linked structure.

[0062] Low-temperature elasticity retention rate is a key indicator for measuring whether a material can maintain its elasticity in cold environments. Example 2 achieved 82%, while Comparative Example 2 only reached 63%, highlighting the reinforcing effect of core-shell microspheres on elasticity maintenance at low temperatures and effectively overcoming the problem of elasticity degradation caused by traditional hydrophobic additives at low temperatures.

[0063] The contact angle test showed that Example 2 reached a maximum of 104°, which is much higher than Comparative Example 1 (88°) and Comparative Example 2 (92°), indicating that its surface is more hydrophobic, which is beneficial to further prevent the adsorption and penetration of polar molecules and enhance the interface protection capability.

[0064] In summary, this invention significantly improves the overall performance of butyl rubber diaphragm materials in resisting the penetration of water vapor and volatile organic compounds by constructing a triple synergistic barrier system of "layered directional barrier - dynamic interface sealing - hydrophobic network interception".

[0065] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0066] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A high-barrier butyl rubber septum material for preventing volatile cross-contamination, characterized in that, It contains the following raw materials in parts by weight: 90-110 parts butyl rubber, 5-12 parts oriented lamellar filler, 2-5 parts silane coupling agent containing dynamic bonds, 1-3 parts polyisobutylene core-fluorinated hydrophobic core-shell microspheres, 1.5-3 parts vulcanizing agent, 0.8-2 parts vulcanization accelerator, and 3-5 parts activator.

2. The high-barrier butyl rubber septum material for preventing volatile cross-contamination according to claim 1, characterized in that, The directional sheet filler is selected from one or more of the following: organically modified montmorillonite, hydrophobically modified graphene, organically modified attapulgite, hydrophobically modified vermiculite, and organically modified bentonite.

3. The high-barrier butyl rubber septum material for preventing cross-contamination of volatiles according to claim 1, characterized in that, The Mooney viscosity ML(1+8)100 °C of the butyl rubber is 45-60; when the oriented sheet filler is organically modified montmorillonite, its interlayer spacing is 2.5-4.0 nm; when the oriented sheet filler is hydrophobically modified graphene, its aspect ratio is not less than 300.

4. The high-barrier butyl rubber septum material for preventing cross-contamination of volatiles according to claim 1, characterized in that, The silane coupling agent containing dynamic bonds is 5-(1,2-dithioalkyl-3-yl)-N-[3-(triethoxysilyl)propyl]pentanamide.

5. The high-barrier butyl rubber septum material for preventing cross-contamination of volatiles according to claim 1, characterized in that, The method for synthesizing the silane coupling agent containing dynamic bonds includes the following steps: under nitrogen protection, thioctic acid and aminopropyltriethoxysilane are added to the organic solvent N,N-dimethylformamide in a molar ratio of 1:1.05 to 1:1.1, and 4-dimethylaminopyridine is added as a catalyst at a mass ratio of 2% to 3% relative to the total mass of the reactants. After the reaction is completed, the mixture is purified by vacuum distillation to obtain the silane coupling agent containing dynamic bonds.

6. The high-barrier butyl rubber septum material for preventing volatile cross-contamination according to claim 1, characterized in that, In the polyisobutylene core-fluorinated hydrophobic core-shell microspheres, the core layer is polyisobutylene, and the shell layer is selected from polyvinylidene fluoride or polychlorotrifluoroethylene; the particle size of the core-shell structure microspheres is 50-200 nm, and the mass ratio of the core layer to the shell layer is 3:1-5:

1.

7. The high-barrier butyl rubber septum material for preventing volatile cross-contamination according to claim 1, characterized in that, The vulcanizing agent is sulfur; the vulcanization accelerator is selected from one or more of thiuram accelerators and dithiocarbamate accelerators, wherein the thiuram accelerators include TMTD, TMTM, and TETD, and the dithiocarbamate accelerators include ZDBC, ZDMC, and ZDEC; the activator is a mixture of zinc oxide and stearic acid, wherein the mass ratio of zinc oxide to stearic acid is 3:1 to 4:

1.

8. A method for preparing a high-barrier butyl rubber septum material for preventing cross-contamination as described in claim 1, characterized in that, Includes the following steps: S1. Add the oriented sheet packing to the mixing equipment, then add the silane coupling agent containing dynamic bonds, and mix and stir to obtain the modified sheet packing; S2. Add butyl rubber to the plasticizing equipment for plasticizing, and then add modified lamellar filler, polyisobutylene core-fluorinated hydrophobic core-shell microspheres, and activator in sequence, and continue to mix to form a rubber blend; S3. Add vulcanizing agent and vulcanization accelerator to rubber blend, mix and under shearing action to make the oriented lamellar filler be oriented; S4. The mixed rubber compound is placed into a molding equipment for molding and vulcanization. After molding and vulcanization, post-vulcanization treatment is performed. After cooling to room temperature, it is cut to obtain the butyl rubber diaphragm material.

9. The method for preparing the high-barrier butyl rubber septum material for preventing cross-contamination of volatiles according to claim 8, characterized in that, In step S1, the mixing temperature is 80-90℃, the mixing time is 30-40 min, and the mixing speed is 1500-2000 r / min; in step S2, the plasticizing temperature is 100-110℃, the plasticizing time is 5-8 min, the mixing time is 10-15 min, the internal mixer rotor speed is 40-60 r / min, and the filling coefficient is 0.6-0.

7.

10. The method for preparing the high-barrier butyl rubber septum material for preventing cross-contamination of volatiles according to claim 8, characterized in that, In step S3, the mixing temperature is 120–130℃, the mixing time is 8–12 min, and the shear rate is 500–800 s⁻¹; in step S4, the molding vulcanization temperature is 150–160℃, the molding vulcanization pressure is 15–20 MPa, the molding vulcanization time is 15–20 min, the post-vulcanization temperature is 100–110℃, and the post-vulcanization time is 4–6 h.

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