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CN-121991423-A - Sealing ring material with low temperature resistance and good sealing performance and preparation method thereof

CN121991423ACN 121991423 ACN121991423 ACN 121991423ACN-121991423-A

Abstract

The invention provides a sealing ring material with low temperature resistance and good sealing performance and a preparation method thereof, and relates to the technical field of high polymer materials. Comprises 95-105 parts of hydrogenated nitrile rubber, 15-30 parts of phase-change microcapsule, 20-35 parts of spherical nano silicon dioxide with double-function modified surface, 8-15 parts of plasticizer, 3-8 parts of liquid fluororubber, 4-7 parts of peroxide, 2-5 parts of cross-linking agent, 1-2 parts of antioxidant and 1-2 parts of processing aid. Solves the problems that the existing sealing ring material has too high compression set rate under static compression at ultra-low temperature (such as-70 ℃) for a long time, and has too fast attenuation of sealing force under severe temperature circulation (-80 ℃ to 25 ℃), and meanwhile, has biocompatibility risks.

Inventors

  • HAN JINGYI
  • Fan Maosen

Assignees

  • 山东大学齐鲁医院
  • 优利芬(山东)生物科技有限公司

Dates

Publication Date
20260508
Application Date
20260128

Claims (10)

  1. 1. The sealing ring material with low temperature resistance and good sealing performance is characterized by comprising the following components in parts by weight: 95-105 parts of hydrogenated nitrile rubber, 15-30 parts of phase-change microcapsule, 20-35 parts of spherical nano silicon dioxide with double-function modified surface, 8-15 parts of plasticizer, 3-8 parts of liquid fluororubber, 4-7 parts of peroxide, 2-5 parts of cross-linking agent, 1-2 parts of antioxidant and 1-2 parts of processing aid.
  2. 2. The sealing ring material with low temperature resistance and good sealing performance according to claim 1, wherein the wall material of the phase-change microcapsule is melamine resin, the core material is C16-C20 straight-chain alkane mixture, and the phase-change point is-45 ℃ to-35 ℃.
  3. 3. The sealing ring material with good sealing performance and low temperature resistance according to claim 2, wherein the preparation method of the phase-change microcapsule comprises the following steps: (1) Mixing melamine and formaldehyde solution with deionized water, regulating the pH to 8.5-9.0, and heating to 70-75 ℃ for reaction to obtain melamine prepolymer solution; (2) Mixing a C16-C20 straight-chain alkane mixture, a styrene-maleic anhydride copolymer sodium salt and alkylphenol ethoxylates, adding 60-70 ℃ deionized water, pre-emulsifying at 5000-8000rpm, and homogenizing for 2-4 times under 30-50MPa to obtain an oil-in-water emulsion; (3) Heating the oil-in-water emulsion to 55-60 ℃ at a stirring speed of 200-400rpm, regulating the pH to 4.5-5.5, slowly dripping the melamine prepolymer solution, and heating to 60-65 ℃ after dripping is finished to continuously react to form a wall material; (4) Regulating pH to 7.0-8.0, adding solidifying agent, heating to 75-80deg.C, cooling, centrifuging, washing, and drying to obtain phase change microcapsule.
  4. 4. A low temperature resistant and well-sealable gasket material according to claim 3, wherein the C16-C20 linear alkane mixture comprises, by mass fraction, 20-35% n-hexadecane, 30-45% n-octadecane and 25-40% n-eicosane.
  5. 5. A low temperature resistant and sealing gasket material according to claim 3, wherein the mass ratio of the sum of the melamine and formaldehyde components to the C16-C20 linear alkane mixture is (1.2-1.8): 1; and/or the mole ratio of melamine to formaldehyde is controlled to be 1 (3-3.5); and/or styrene-maleic anhydride copolymer sodium salt accounting for 3-8% of the mass of the mixture of C16-C20 linear alkane; and/or alkylphenol ethoxylates accounting for 1-3% of the mass of the mixture of the C16-C20 linear alkane.
  6. 6. The low temperature resistant and good sealing ring material as claimed in claim 1, wherein the preparation method of the spherical nano silicon dioxide with the surface modified by double functions comprises the following steps: (1) Mixing octadecyltrimethoxy silane, 3-mercaptopropyl trimethoxy silane and anhydrous toluene, dropwise adding a trace amount of water at 0-5 ℃ under the protection of nitrogen, and then adding an organic amine catalyst for pre-hydrolysis to obtain a bifunctional silane hydrolysate; mixing the dried spherical nano silicon dioxide with anhydrous toluene, heating to 80-90 ℃ under the protection of nitrogen, refluxing for 1-2h, and then cooling to 40-50 ℃ to obtain a suspension; (2) Dripping the bifunctional silane hydrolysis liquid into the suspension, keeping the reaction temperature at 40-50 ℃, stirring at 400-600rpm, heating to 110-120 ℃ after the dripping, refluxing for 12-24h, and then performing post-treatment to obtain the spherical nano silicon dioxide with the surface modified by double functions.
  7. 7. The sealing ring material with low temperature resistance and good sealing performance according to claim 6, wherein octadecyltrimethoxysilane accounts for 15-25% of the mass of the spherical nano silicon dioxide; And/or the 3-mercaptopropyl trimethoxy silane accounts for 8-15% of the mass of the spherical nano silicon dioxide.
  8. 8. The sealing ring material with low temperature resistance and good sealing performance according to claim 6, wherein the average particle size of the spherical nano silicon dioxide is 10-30nm, the specific surface area is 150-250m 2 /g, and the surface silicon hydroxyl density is more than or equal to 3 silicon hydroxyl groups/nm 2 .
  9. 9. The sealing ring material with good sealing performance and low temperature resistance according to claim 1, wherein the plasticizer is at least one of dioctyl adipate, dioctyl sebacate or trioctyl trimellitate; and/or the liquid fluororubber is a perfluoropolyether; And/or the peroxide is one or two of 2, 5-dimethyl-2, 5-di (tert-butylperoxy) hexane or dicumyl peroxide; and/or the cross-linking agent is one or two of triallyl isocyanurate or trimethylolpropane trimethacrylate; and/or the antioxidant is one or two of antioxidant 1010 and antioxidant 168; and/or the processing aid is a polyethylene wax.
  10. 10. A method for preparing a sealing ring material with low temperature resistance and good sealing performance according to any one of claims 1 to 9, characterized in that the preparation method comprises the following steps: S1, plasticating hydrogenated nitrile rubber, adding liquid fluororubber and a part of plasticizer, mixing at 60-70 ℃, adding spherical nano silicon dioxide with the surface modified by double functions, mixing at 70-80 ℃, adding an antioxidant, a processing aid and another part of plasticizer, mixing at 75-85 ℃, and discharging rubber to obtain master batch; s2, adding the phase-change microcapsule into the masterbatch, and mixing at the temperature of 40-50 ℃; And S3, adding peroxide and a cross-linking agent, continuously mixing, and performing vulcanization molding at 160-170 ℃ to obtain the sealing ring material.

Description

Sealing ring material with low temperature resistance and good sealing performance and preparation method thereof Technical Field The invention relates to the technical field of high polymer materials, in particular to a sealing ring material with low temperature resistance and good sealing performance and a preparation method thereof. Background The preservation of the activity of a microbial sample (e.g., cells, species, viruses, tissue, etc.) is highly dependent on a stable ultra-low temperature environment. Dedicated refrigerated transport cases (liquid nitrogen gas phase or mechanical refrigeration environment, typically operating at-40 ℃ to-196 ℃) are critical equipment to ensure that the quality of the sample is unchanged during the logistics process. The sealing system of the box body, in particular to a sealing ring, is a core component for preventing external heat from entering and internal refrigerant from leaking or volatile components of a sample from escaping, and the performance of the sealing system directly determines the constancy of the temperature in the box and the purity of the sample. Currently, sealing ring materials applied to low-temperature environments mainly include silicone rubber (VMQ), fluorosilicone rubber (FVMQ), ethylene propylene diene monomer rubber (EPDM), fluororubber (FKM) and the like. Although these materials have a certain performance at conventional low temperatures, when applied to long-term, extremely low-temperature and absolutely biosafety-demanding transportation scenarios for microbial samples, there are a series of inherent drawbacks that are not adequately addressed, specifically: (1) The low temperature resistance of the existing material is mostly based on short-time test, and in practical application, the sealing ring needs to bear continuous static compression and ultralow temperature (below-70 ℃ for example) for a plurality of weeks or even months after the box body is locked. Under this severe regime, polymer molecular chain segment motion is "frozen" and the stress relaxation process accelerates, resulting in irreversible plastic deformation. For example, conventional Fluororubbers (FKM) or higher hardness silicone rubbers generally have Compression Set (CS) of over 60% or even as high as 80% after static compression for 30 days in a-70℃environment. This means that the cross-sectional height of the seal ring is significantly reduced and the resilience is lost. When the box body is required to be temporarily opened in the transportation process due to inspection or transfer, the sealing ring cannot recover the original shape, so that the secondary sealing after repeated opening and closing is invalid, and the temperature stability in the box is seriously endangered. (2) The transportation process inevitably undergoes links such as loading, unloading, transferring and the like, so that the interface of the sealing ring bears multiple abrupt temperature shocks from normal temperature (25 ℃) to ultralow temperature (-80 ℃ or lower). In the repeated thermal expansion and contraction process of the existing material system, micro cracks and interface debonding are easy to generate due to mismatching of thermal expansion coefficients of components and structural change of micro areas in the matrix. After over 20-80 ℃ to 25 ℃ temperature cycles, the seal contact pressure (i.e., sealing force) of conventional low temperature resistant rubber materials typically decays by over 30%. This attenuation is gradual and irreversible, making the tank susceptible to leakage during vibration or slight deformation. (3) In order to improve processability or low temperature performance, conventional sealing ring formulations are often added with small molecular plasticizers such as phthalates which are easy to migrate, certain sulfur vulcanization system residues or insufficiently crosslinked oligomers. In ultra-low temperature and relatively closed box interior environments, these materials may slowly volatilize (VOC precipitation) or migrate in contact with volatile components of sample protectants (e.g., DMSO), with the potential risk of inhibiting or even poisoning the activity of the precious microbial sample. The existing industry seal ring standards do not adequately address such biocompatibility requirements. Therefore, developing a sealing ring material with excellent long-term compression set recovery capability, excellent temperature cycle fatigue resistance, high chemical inertness and biosafety has become an urgent technical need for improving the reliability of high-end biological cold chain equipment. The present invention is directed to overcoming at least one or more of the shortcomings of the prior art set forth above. Disclosure of Invention In order to solve the above problems, a first aspect of the present invention provides a sealing ring material with low temperature resistance and good sealing property, which includes, in parts by weight: 95-105 pa