A gas adsorption type optical fiber jelly for hollow core optical fiber, an optical cable and a preparation method thereof

Abstract

The application belongs to the technical field of optical fiber grease, and more particularly relates to a gas adsorption type fiber grease for hollow core optical fiber, an optical cable and a preparation method thereof. The gas adsorption type fiber grease for hollow core optical fiber comprises MOFs porous adsorption material with hydrophobic modification. The introduction of the porous adsorption material can continuously adsorb harmful gas penetrating in the process of production and use of the optical cable, so that the gas is prevented from penetrating into the optical fiber to cause attenuation of the optical fiber.

Description

Technical Field

[0001] This application belongs to the field of optical fiber grease technology, and more specifically, relates to a gas adsorption type fiber grease for hollow optical fibers, an optical cable, and a method for preparing the same. Background Technology

[0002] Hollow-core optical fiber is a type of optical fiber based on the principle of microstructured photonic bandgap or anti-resonance. Its core is an air channel, which can significantly reduce nonlinear effects and delay, making it suitable for high-power laser transmission, low-latency communication, and other fields. However, the hollow-core structure also presents key challenges. Due to its unique structure, gas permeation is prone to occur during production, cabling, and use. External gases (such as H2O, CO2, and CO) can seep into the hollow-core fiber, leading to light scattering and absorption losses, and increasing fiber attenuation. Traditional sealing methods have limitations, relying on purely physical methods to seal the fiber ends, such as fusion splicing, sealing with adhesive, or end cap encapsulation. However, the high temperatures and mechanical stresses during secondary coating processes can easily compromise the seal, allowing gas to permeate. Currently, traditional sealing methods cannot solve the gas permeation problem during the production stage, especially during secondary coating. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the purpose of this application is to provide an optical fiber grease (hereinafter referred to as fiber grease) that can efficiently and persistently absorb harmful gases. By introducing specifically modified MOFs materials, the gas permeation problem of hollow optical fibers can be solved.

[0004] To achieve the above objectives, in a first aspect, this application provides a gas-adsorption type fiber paste for hollow optical fibers, comprising, by weight, 80-95 parts of base oil, 5-15 parts of thickener, 0.1-1 parts of antioxidant, and 0.5-5 parts of hydrophobically modified MOF material.

[0005] The hydrophobically modified MOF material is a material synthesized by using hydrophobic molecules as co-ligands during the synthesis of the MOF material.

[0006] Preferably, the MOF material is one or more of the ZIFs series, UiOs series, and MILs series.

[0007] Preferably, when the MOF material is a ZIFs series, the hydrophobic molecule is a hydrophobic imidazole molecule with 5-20 carbon atoms; when the MOF material is a UiOs series or MILs series, the hydrophobic molecule is a hydrophobic alkyl carboxylic acid with 5-20 carbon atoms.

[0008] More preferably, the hydrophobic imidazole molecule is one or more of the following: branched alkyl imidazoles with 5-20 carbon atoms, long-chain alkyl imidazoles with 5-20 carbon atoms, fluorinated imidazoles with 5-20 carbon atoms, and fluorinated ionic liquids with 5-20 carbon atoms.

[0009] Preferably, in the synthesis of the hydrophobically modified MOF material, the ligand corresponding to the MOF material is the first ligand, the hydrophobic molecule is the second ligand, and the molar ratio of the first ligand to the second ligand is (1-10):1.

[0010] Another objective of this invention is to provide a method for preparing the aforementioned fiber paste, which solves the problems of MOF aggregation and dispersion stability in oil pastes through innovative material modification and multi-stage dispersion processes. The method for preparing the fiber paste includes the following steps: dispersing the hydrophobically modified MOF material in an organic solvent to form a MOF slurry; then mixing the slurry uniformly with the base oil, thickener, and antioxidant; and finally removing the organic solvent by vacuum distillation to obtain the fiber paste.

[0011] Preferably, the preparation method specifically includes the following steps:

[0012] S1: The hydrophobically modified MOF material is dispersed in an organic solvent and then ultrasonically treated to form a uniform and stable MOF slurry;

[0013] S2: The MOF slurry obtained in step S1 is added to the preheated base oil under stirring conditions to form a primary mixture;

[0014] S3: Add the thickener and antioxidant to the primary mixture of step S2, and allow the thickener to fully swell under heating and stirring conditions to homogenize the system;

[0015] S4: Remove the organic solvent from the mixture obtained in step S3 under reduced pressure and heating conditions;

[0016] S5: The product obtained in step S4 is homogenized and vacuum degassed to obtain the fiber paste product.

[0017] More preferably, the ultrasonic treatment in step S1 is ultrasonic breakage of the probe under ice-water bath cooling.

[0018] More preferably, the heating temperature in step S4 is 60-75℃, and the absolute pressure of the system is not higher than 15 kPa.

[0019] According to another aspect of the present invention, a hollow optical fiber cable is provided, comprising a hollow optical fiber and a secondary coating layer, wherein the surface of the hollow optical fiber is coated with the fiber paste, and the fiber paste fills the space between the hollow optical fiber and the secondary coating layer. The hydrophobically modified MOF material contained in the fiber paste is a porous adsorbent material that can continuously adsorb harmful gases that permeate during the production and use of the optical cable, thereby preventing gas from penetrating into the optical fiber and causing optical fiber attenuation.

[0020] According to another aspect of the present invention, a hybrid optical cable is also provided, which is formed by mixing solid optical fiber cable and hollow optical fiber cable, wherein the solid optical fiber cable includes at least one solid optical fiber unit, the solid optical fiber unit includes a loose tube and multiple solid optical fibers wrapped in the loose tube, and the solid optical fibers are G.652D, G.654E or G.655.

[0021] Overall, the technical solutions conceived in this application have the following beneficial effects compared with the prior art:

[0022] (1) The gas adsorption type fiber paste for hollow optical fiber proposed in this invention contains a MOF porous adsorbent material with hydrophobic modification. The introduction of this porous adsorbent material can continuously adsorb harmful gases that have seeped in during the production and use of optical cables, thereby preventing gas from penetrating into the optical fiber and causing optical fiber attenuation.

[0023] (2) The present invention initially attempted to introduce metal-organic framework (MOF) materials into fiber paste in order to utilize their porous adsorption properties to adsorb harmful gases and thus prevent gas from permeating into hollow optical fibers. However, experiments showed that MOFs were difficult to disperse uniformly in the paste when directly introduced. Therefore, the present invention proposes to use hydrophobic imidazole molecules as co-ligands in the synthesis of MOF materials to obtain hydrophobically modified MOF materials. By using hydrophobic imidazole molecules as co-ligands, the surface properties of metal-organic framework materials (MOF) are changed at the molecular level, giving them intrinsic hydrophobicity and fundamentally improving their compatibility with the paste matrix.

[0024] (3) In the preparation process of the gas adsorption type fiber paste of the present invention, a multi-stage dispersion process of "solvent dispersion first, then solvent removal" is adopted, which effectively solves the problem of agglomeration of nano MOF particles in high viscosity paste and realizes micro-uniform dispersion of MOF.

[0025] (4) Tests show that the gas adsorption grease for hollow optical fibers proposed in this invention has the following technical advantages: 1) High efficiency in gas absorption: The hydrophobically modified MOF material maintains a high specific surface area and microporous structure, and has excellent adsorption capacity and rate for harmful gases; 2) Long-term stability: The hydrophobically modified MOF material is stably dispersed in the grease, without sedimentation or agglomeration, ensuring the durability of gas adsorption performance; 3) Good compatibility: It does not affect the original key physical indicators of the grease, such as dropping point and cone penetration; 4) Industrial value: It provides a reliable active optical fiber harmful gas adsorption solution with mature technology, suitable for large-scale production, and can significantly improve and extend the service life of optical cables. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the hollow optical fiber cable provided in the embodiments of this application;

[0027] Figure 2 These are the XRD diffraction patterns of ZIF-8 crystals before and after hydrophobic modification provided in Example 1-1 of this application;

[0028] Figure 3 These are the test results of the gas absorption performance of the fiber paste provided in the embodiments and comparative examples of this application;

[0029] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0030] 1-Hollow fiber; 2-Fiber grease; 3-Secondary coating. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0032] This invention addresses the problem of gas permeation in hollow optical fibers by proposing a gas-adsorption fiber paste. This paste is applied to the surface of the hollow optical fiber during the secondary coating stage, protecting the fiber from gas permeation through a dual mechanism of chemical adsorption and physical barrier. Metal-organic frameworks (MOFs), such as ZIFs, UiOs, and MILs series, especially ZIF series MOFs, possess high specific surface area and well-defined microporous structures, exhibiting excellent adsorption performance for the aforementioned gases. However, directly applying MOFs to fiber pastes faces the following technical bottlenecks: MOFs have hydrophilic surfaces, resulting in poor compatibility with hydrophobic paste matrices and a tendency for phase separation; nanoscale MOF particles easily agglomerate in viscous pastes, making uniform dispersion difficult and severely impacting gas absorption efficiency; traditional mechanical mixing methods cannot achieve nanoscale dispersion of MOFs in pastes, leading to excessively high local concentrations and affecting the physical properties of the paste. Therefore, there is an urgent need to develop a novel fiber paste that combines excellent gas absorption performance with good dispersion stability.

[0033] Therefore, this invention provides a gas-adsorption type fiber paste for hollow optical fibers, comprising, by weight, 80-95 parts base oil, 5-15 parts thickener, 0.1-1 parts antioxidant, and 0.5-5 parts hydrophobically modified MOF material; the hydrophobically modified MOF material is obtained by using hydrophobic molecules as co-ligands in the synthesis process of the MOF material. This invention proposes using hydrophobic imidazole molecules as co-ligands in the synthesis process of MOF materials to obtain hydrophobically modified MOF materials. By using hydrophobic imidazole molecules as co-ligands, the surface properties of metal-organic framework materials (MOFs) are changed at the molecular level, giving them intrinsic hydrophobicity and fundamentally improving their compatibility with the paste matrix.

[0034] In some embodiments, the MOF material is one or more of the ZIFs series, UiOs series, and MILs series. The ZIFs series includes, but is not limited to, one or more of ZIF-8, ZIF-67, ZIF-7, ZIF-11, ZIF-90, ZIF-71, ZIF-95, and ZIF-100.

[0035] In some embodiments, when the MOF material is a ZIFs series, the hydrophobic molecule is a hydrophobic imidazole molecule with 5-20 carbon atoms, specifically including but not limited to one or more of branched alkyl imidazoles with 5-20 carbon atoms (preferably 10-15 carbon atoms), long-chain alkyl imidazoles with 5-20 carbon atoms, fluorinated imidazoles with 5-20 carbon atoms, and fluorinated ionic liquids with 5-20 carbon atoms; the hydrophobic imidazole molecule used in the ZIFs series MOF is an imidazole molecule that provides steric hindrance to hydrophobically modify the ZIFs series material. In a preferred embodiment, the hydrophobic imidazole molecule is one or more of the following: 1-hexylimidazolium, 1-octylimidazolium, 1-dodecylimidazolium, 1-hexadecylimidazolium, 1-octadecylimidazolium, 1-hexyl-3-methylimidazolium (HMIM), 1-octyl-3-methylimidazolium (OMIM), 1-decyl-3-methylimidazolium (DMIM), 1-dodecyl-3-methylimidazolium (C12MIM), 1-hexadecyl-3-methylimidazolium, 1-benzylimidazolium, 1-(1-naphthylmethyl)imidazolium, 1-triphenylmethylimidazolium, 1-(perfluorohexyl)imidazolium, 1-(1H,1H,2H,2H-perfluorooctyl)imidazolium, and 1-methyl-3-(1H,1H,2H,2H-perfluorooctyl)imidazolium.

[0036] When the MOF material is a UiOs series or a MILs series, the hydrophobic molecule is a hydrophobic alkyl carboxylic acid with 5-20 carbon atoms (preferably 10-15 carbon atoms). For example, the main ligand of MIL-100 is pyromellitic acid, and in some embodiments, dodecyl carboxylic acid is used as a co-ligand to provide steric hindrance for hydrophobic modification; the main ligand of UiO-66 is terephthalic acid, and in some embodiments, dodecyl carboxylic acid is used as a co-ligand to provide steric hindrance for hydrophobic modification.

[0037] In some embodiments, during the synthesis of the hydrophobically modified MOF material, the ligand corresponding to the MOF material is the first ligand, and the hydrophobic molecule serves as the second ligand, i.e., the co-ligand described in this invention. The molar ratio of the first ligand to the second ligand is (1-10):1. The ligand corresponding to the MOF material is also referred to as the organic linker used in the synthesis of the MOF material, or as the pillar ligand serving as the main structural building block. Taking ZIF-8 MOF material as an example, the first ligand during synthesis is 2-methylimidazole, and the second ligand is hexylimidazole. Hexylimidazole is also used as the co-ligand in the synthesis of ZIF-8. The molar ratio of 2-methylimidazole to hexylimidazole is (1-10):1.

[0038] The base oil, thickener, and antioxidant used in this invention are conventional components commonly used in fiber pastes. In some embodiments, the base oil is mineral oil, synthetic hydrocarbon oil, or a mixture thereof; the thickener is polyisobutylene, hydrogenated styrene-butadiene copolymer, or a combination thereof; and the antioxidant is one or more of phenolic antioxidants and phosphorus antioxidants.

[0039] The present invention also provides a method for preparing the aforementioned fiber paste, comprising the following steps: dispersing the hydrophobically modified MOF material in an organic solvent to form a MOF slurry, then mixing the slurry with the base oil, thickener and antioxidant evenly, and then removing the organic solvent by vacuum distillation to obtain the fiber paste.

[0040] In some embodiments, the preparation method specifically includes the following steps:

[0041] S1: Slurry preparation: The hydrophobically modified MOF material is dispersed in an organic solvent and ultrasonically treated to form a uniform and stable MOF slurry;

[0042] S2: Primary mixing: The MOF slurry obtained in step S1 is added to the preheated base oil under stirring conditions to form a primary mixture;

[0043] S3: Integration and molding: The thickener and antioxidant are added to the primary mixture in step S2, and the thickener is fully swollen under heating and stirring conditions to homogenize the system;

[0044] S4: Solvent removal: Remove the organic solvent from the mixture obtained in step S3 under reduced pressure and heating conditions;

[0045] S5: Post-processing: The product obtained in step S4 is homogenized and vacuum degassed to obtain the fiber paste product.

[0046] In some embodiments, the organic solvent in step S1 is one or more of acetone, methyl ethyl ketone (MEK), N,N-dimethylformamide (DMF), and ethanol.

[0047] In some embodiments, the ultrasonic treatment in step S1 involves ultrasonic fragmentation of the probe under ice-water bath cooling. The probe has high ultrasonic power (400-600W) and generates significant heat. Acetone has a low boiling point, and the ice-water bath can control the reaction temperature, preventing solvent evaporation and excessively high slurry temperature, avoiding potential damage to the ZIF-8 structure, and ensuring operational safety. The probe ultrasound directly transmits high-intensity ultrasonic energy into the sample solution, resulting in concentrated energy and better dispersion efficiency and effect.

[0048] In some embodiments, the heating temperature in step S4 is 60-75°C, and the system absolute pressure is no higher than 15 kPa, for example, 10 kPa to 15 kPa. These conditions can further improve solvent removal efficiency and optimize product performance.

[0049] In preparing the ointment, the hydrophobically modified MOF material is first dispersed in an organic solvent to form a slurry, which is then mixed and dispersed with base oil, thickener and antioxidant. Finally, the organic solvent is removed by vacuum distillation. This preparation method ingeniously solves the problem of agglomeration of nano MOF particles in high-viscosity ointments and achieves microscopic uniform dispersion of MOF.

[0050] The present invention also provides a hollow optical fiber cable, such as Figure 1 As shown, the optical cable includes a hollow fiber 1 and a secondary coating layer 3. The surface of the hollow fiber is coated with the fiber paste 2 described in this invention, which fills the space between the hollow fiber 1 and the secondary coating layer 3. The hydrophobically modified MOF material contained in the fiber paste is a porous adsorbent material that can continuously adsorb harmful gases that permeate during the production and use of the optical cable (since the optical fiber cannot be sealed during production, the adsorption demand for harmful gases is relatively large during production; during normal use, the optical fiber end is sealed, so the demand for harmful gases is relatively small), thus preventing gas from penetrating into the optical fiber and causing optical fiber attenuation.

[0051] In some embodiments, the preparation of the hollow optical fiber cable includes the following steps: coating the surface of the hollow optical fiber with the gas adsorption grease; then performing loose tube extrusion or armoring processes to form an optical cable structure; and continuously adsorbing harmful gases that permeate during the optical cable production process through the porous adsorption material in the grease.

[0052] The hollow-core optical fiber cable described in this invention is suitable for high-power laser transmission, low-latency communication, or quantum communication.

[0053] This application also provides a hybrid optical cable formed by combining hollow-core optical fiber cable and solid-core optical fiber cable. The hollow-core optical fiber cable can adopt the structure of the hollow-core optical fiber cable described above in this invention. The solid-core optical fiber cable can include at least one existing solid-core optical fiber unit. The solid-core optical fiber unit includes a loose tube and multiple solid optical fibers wrapped in the loose tube. The solid optical fibers can be G.652D, G.654E or G.655, etc.

[0054] The embodiments of the present invention are implemented under the premise of the technical solution of the present invention, and detailed implementation methods and processes are given. However, the protection scope of the present invention is not limited to the following embodiments. The process parameters in the following embodiments that do not specify specific conditions are generally in accordance with conventional conditions.

[0055] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0056] The process parameters in the following examples, unless otherwise specified, are generally performed under conventional conditions.

[0057] The embodiments of this application are described below with reference to the accompanying drawings.

[0058] Example 1-1

[0059] Synthesis of hydrophobically modified ZIF-8:

[0060] Weigh out 2-methylimidazole (1.64 g, 20 mmol) and 1-hexylimidazole (0.62 g, 4 mmol) and dissolve them in 40 mL of methanol, which is denoted as solution A.

[0061] Weigh out 2.97 g (10 mmol) of zinc nitrate hexahydrate and dissolve it in 40 mL of methanol, and denote this solution as solution B.

[0062] While stirring at room temperature, quickly pour solution A into solution B and continue stirring for 24 hours.

[0063] After the reaction was complete, the white precipitate was collected by centrifugation and washed three times with methanol.

[0064] The product was dried in a vacuum drying oven at 80°C for 12 hours to obtain hydrophobically modified ZIF-8 powder.

[0065] Comparative Example 1-1

[0066] Synthesis of ordinary ZIF-8:

[0067] Weigh out 1.64 g (20 mmol) of 2-methylimidazole and dissolve it in 40 mL of methanol, which is recorded as solution A.

[0068] Weigh out 2.97 g (10 mmol) of zinc nitrate hexahydrate and dissolve it in 40 mL of methanol, and denote this solution as solution B.

[0069] While stirring at room temperature, quickly pour solution A into solution B and continue stirring for 24 hours.

[0070] After the reaction was complete, the white precipitate was collected by centrifugation and washed three times with methanol.

[0071] The product was dried in a vacuum drying oven at 80°C for 12 hours to obtain ZIF-8 powder.

[0072] The organic framework materials obtained from hydrophobically modified ZIF-8 in Example 1-1 and from ordinary ZIF-8 powder synthesized in Comparative Example 1-1 were characterized as follows:

[0073] BET testing showed that the specific surface area of ​​the material in Example 1-1 was 1600 m². 2 / g, compared with Comparative Example 1-1 (1650m) 2 The result is equivalent to / g), proving that the modification did not destroy its porous structure.

[0074] Water contact angle tests showed that the contact angle of the material in Example 1 was 125°, while that in Comparative Example 1 was only 65°, demonstrating a significant improvement in hydrophobicity.

[0075] XRD patterns show that the crystal structure of ZIF-8 remains consistent before and after hydrophobic modification, proving that the modification was successful and maintained the crystal framework of ZIF-8. Figure 2 As shown.

[0076] Examples 1-2

[0077] Preparation of the fiber paste:

[0078] 2.0 g of the hydrophobic modified ZIF-8 prepared in Example 1-1 was dispersed in 50 mL of acetone. It was first sheared at 5000 rpm for 5 minutes, and then ultrasonically treated with a probe in an ice-water bath (power 500W, working for 2 seconds, intermittent for 3 seconds, total duration 15 minutes) to obtain a uniform slurry.

[0079] Take 150 g of mineral oil (100SN) and place it in a 500 mL reaction flask equipped with stirring and heating. Preheat the flask to 50°C and slowly and evenly add the above MOF slurry to the preheated base oil while stirring at 400 rpm. After the addition is complete, continue stirring for 30 minutes to form a primary mixture.

[0080] Add 20 g of polyisobutylene (PIB, Daelim, Korea, PB950) thickener and 0.5 g of antioxidant BHT to the primary mixture, heat to 80°C, increase the stirring speed to 800 rpm, and continue stirring for 2 hours until the system is uniformly viscous.

[0081] The reaction system was transferred to a vacuum distillation apparatus and distilled at 70°C and 11.3 kPa absolute pressure for 1 hour until no more distillate was distilled off.

[0082] The resulting paste was ground three times using a three-roll mill and then defoamed using a vacuum defoaming machine to obtain the final fiber paste product.

[0083] Comparative Examples 1-2

[0084] The rest is the same as in Examples 1-2, except that 2.0g of hydrophobically modified ZIF-8 is directly added to the base oil without a solvent dispersion step. After mechanical mixing, the ointment is prepared according to the same steps. The specific preparation method is as follows:

[0085] Take 150 g of mineral oil (100SN) and place it in a 500 mL reaction flask equipped with stirring and heating. Preheat to 50°C and add 2.0 g of hydrophobic modified ZIF-8 prepared in Example 1-1 while stirring at 400 rpm. Continue stirring for 30 minutes.

[0086] Add 20 g of polyisobutylene (PIB, Daelim, Korea, PB950) thickener and 0.5 g of antioxidant BHT to the system, heat to 80°C, increase the stirring speed to 800 rpm, and continue stirring for 2 hours until the system is uniformly viscous.

[0087] The reaction system was transferred to a vacuum distillation apparatus and distilled at 65°C and -0.09 MPa for 1 hour until no more distillate was distilled off.

[0088] The resulting paste was ground three times using a three-roll mill and then defoamed using a vacuum defoaming machine to obtain the final fiber paste product.

[0089] Comparative Example 2-2

[0090] The rest is the same as in Examples 1-2, except that the hydrophobic modified ZIF-8 is replaced with the ordinary ZIF-8 material of Comparative Example 1-1.

[0091] Comparative Example 3-2

[0092] The rest is the same as Comparative Examples 1-2, except that the hydrophobic modified ZIF-8 is replaced with ordinary ZIF-8 material in Comparative Example 1-1.

[0093] Comparative Example 4-2

[0094] A standard ointment, without any ZIF material added, is prepared as follows:

[0095] Place 150 g of mineral oil (100SN) in a 500 mL reaction flask equipped with stirring and heating, and preheat to 50°C;

[0096] Add 20 g of polyisobutylene (PIB, Daelim, Korea, PB950) thickener and 0.5 g of antioxidant BHT to the system, heat to 80°C, increase the stirring speed to 800 rpm, and continue stirring for 2 hours until the system is uniformly viscous.

[0097] The reaction system was transferred to a vacuum distillation apparatus and distilled at 65°C and -0.09 MPa for 1 hour until no more distillate was distilled off.

[0098] The resulting paste was ground three times using a three-roll mill and then defoamed using a vacuum defoaming machine to obtain the final fiber paste product.

[0099] Example 2-1

[0100] Everything else is the same as in Examples 1-1, except that the ZIF material is ZIF-67. The specific preparation method is as follows:

[0101] Synthesis of hydrophobically modified ZIF-67:

[0102] Weigh out 1.64 g (20 mmol) of 2-methylimidazole and 0.44 g (4 mmol) of 2-ethyl-4-methylimidazole and dissolve them in 40 mL of methanol. This solution is labeled as solution A.

[0103] Weigh out 2.91 g (10 mmol) of cobalt nitrate hexahydrate and dissolve it in 40 mL of methanol, and denote it as solution B;

[0104] While stirring at room temperature, quickly pour solution A into solution B and continue stirring for 24 hours.

[0105] After the reaction was complete, the white precipitate was collected by centrifugation and washed three times with methanol.

[0106] The product was dried in a vacuum drying oven at 80°C for 12 hours to obtain hydrophobically modified ZIF-67 powder.

[0107] Example 2-2

[0108] 2.0 g of the hydrophobic modified ZIF-67 prepared in Example 2-1 was dispersed in 50 mL of acetone. It was first sheared at 5000 rpm for 5 minutes, and then ultrasonically treated with a probe in an ice-water bath (power 500W, working for 2 seconds, intermittent for 3 seconds, total duration 15 minutes) to obtain a uniform slurry.

[0109] Take 150 g of mineral oil (100SN) and place it in a 500 mL reaction flask equipped with stirring and heating. Preheat the flask to 50°C and slowly and evenly add the above MOF slurry to the preheated base oil while stirring at 400 rpm. After the addition is complete, continue stirring for 30 minutes to form a primary mixture.

[0110] Add 20 g of polyisobutylene (PIB, Daelim, Korea, PB950) thickener and 0.5 g of antioxidant BHT to the primary mixture, heat to 80°C, increase the stirring speed to 800 rpm, and continue stirring for 2 hours until the system is uniformly viscous.

[0111] The reaction system was transferred to a vacuum distillation apparatus and distilled at 65°C and 12 kPa absolute pressure for 1 hour until no more distillate was distilled off.

[0112] The resulting paste was ground three times using a three-roll mill and then defoamed using a vacuum defoaming machine to obtain the final fiber paste product.

[0113] Example 3-1

[0114] Preparation of hydrophobically modified UiO-66 gas adsorbent material.

[0115] Weigh out terephthalic acid (1.66 g, 10 mmol) and dodecanoic acid (0.40 g, 2 mmol) and dissolve them in 40 mL of N,N-dimethylformamide, and denote this solution as solution A;

[0116] Weigh 1.87 g, 8 mmol of zirconium tetrachloride and dissolve it in 40 mL of N,N-dimethylformamide, and label it solution B. While stirring at room temperature, quickly pour solution A into solution B, then add 1.5 mL of concentrated hydrochloric acid and continue stirring for 24 hours. After the reaction is complete, centrifuge to collect the white precipitate and wash it three times each with DMF and methanol.

[0117] The product was dried in a vacuum drying oven at 120°C for 12 hours to obtain hydrophobically modified UiO-66 powder.

[0118] Example 3-2

[0119] The hydrophobically modified UiO-66 gas adsorbent material was dispersed in a mixed solvent of N,N-dimethylformamide (DMF) and ethanol. It was first sheared at 5000 rpm for 5 minutes, and then ultrasonically treated with a probe in an ice-water bath (power 500W, working for 2 seconds, intermittent for 3 seconds, total duration 15-30 minutes) to form a uniform and stable MOF slurry.

[0120] Take 150 g of mineral oil (100SN) and place it in a 500 mL reaction flask equipped with stirring and heating. Preheat the flask to 50°C and slowly and evenly add the above MOF slurry to the preheated base oil while stirring at 400 rpm. After the addition is complete, continue stirring for 30 minutes to form a primary mixture.

[0121] Add 20 g of thickener (hydrogenated styrene-butadiene block copolymer, Baling Petrochemical SEPS YH-4010, styrene content 37%) and 0.5 g of antioxidant BHT to the primary mixture, heat to 80℃, increase the stirring speed to 800 rpm, and continue stirring for 2 hours until the system is uniformly viscous.

[0122] The reaction system was transferred to a vacuum distillation apparatus and distilled at 70°C and 11.5 kPa absolute pressure for 1 hour until no more distillate was distilled off.

[0123] The resulting paste was ground three times using a three-roll mill and then defoamed using a vacuum defoaming machine to obtain the final fiber paste product.

[0124] Example 4-1

[0125] Synthesis of hydrophobically modified MIL-100 (Fe).

[0126] Weigh out 0.840 g (4 mmol) of pyromellitic acid and 0.080 g (0.4 mmol) of dodecanoic acid and dissolve them in 40 mL of deionized water. This solution is labeled as solution A.

[0127] Weigh out 1.616 g (4 mmol) of ferric nitrate nonahydrate and dissolve it in 40 mL of deionized water, and denote it as solution B. Under stirring at room temperature, quickly pour solution A into solution B and continue stirring for 24 hours. After the reaction is completed, centrifuge to collect the orange-brown precipitate and wash it three times each with hot water and ethanol.

[0128] The product was dried in a vacuum drying oven at 120°C for 12 hours to obtain hydrophobically modified MIL-100(Fe) powder.

[0129] Example 4-2

[0130] The hydrophobically modified MIL-100(Fe) gas adsorbent material was dispersed in a mixed solvent of N,N-dimethylformamide (DMF) and ethanol. It was first sheared at 5000 rpm for 5 minutes, and then ultrasonically treated with a probe in an ice-water bath (power 500W, working for 2 seconds, intermittent for 3 seconds, total duration 15-30 minutes) to form a uniform and stable MOF slurry.

[0131] Take 150 g of mineral oil (100SN) and place it in a 500 mL reaction flask equipped with stirring and heating. Preheat the flask to 50°C and slowly and evenly add the above MOF slurry to the preheated base oil while stirring at 400 rpm. After the addition is complete, continue stirring for 30 minutes to form a primary mixture.

[0132] Add 20 g of thickener (hydrogenated styrene-butadiene block copolymer, Baling Petrochemical SEPSYH-4010, styrene content 37%) and 0.5 g of antioxidant BHT to the primary mixture, heat to 80℃, increase the stirring speed to 800 rpm, and continue stirring for 2 hours until the system is uniformly viscous.

[0133] The reaction system was transferred to a vacuum distillation apparatus and distilled at 70°C and 14 kPa absolute pressure for 1 hour until no more distillate was distilled off.

[0134] The resulting paste was ground three times using a three-roll mill and then defoamed using a vacuum defoaming machine to obtain the final fiber paste product.

[0135] Performance testing and effect verification:

[0136] Dispersion stability test: The greases prepared in Examples 1-2 (hydrophobic modified ZIF-8 + solvent dispersion), Comparative Examples 1-2 (hydrophobic modified ZIF-8 + without solvent dispersion), Comparative Example 2-2 (ordinary ZIF-8 + solvent dispersion), Comparative Example 3-2 (ordinary ZIF-8 + without solvent dispersion), and Comparative Example 4-2 (ordinary grease without ZIF material) were placed in stoppered graduated cylinders and allowed to stand at room temperature for 30 days. The results showed that the grease in Example 1-2 did not show obvious stratification or sedimentation, while the greases in Comparative Examples 1-2, 2-2, and 3-2 showed obvious MOF sedimentation layers at the bottom.

[0137] Gas Absorption Performance Test: A special test cell was prepared (the test cell is a closed, constant-volume reaction system capable of high-precision monitoring of internal pressure changes caused by gas adsorption from the ointment). The test cell contains a fixed sample tray to ensure all ointment samples are tested with the same exposed surface area and coating thickness. During testing, interference from air, water vapor, and other gases is eliminated. A high-precision, fast-response pressure sensor is connected, along with a data acquisition system, to record the pressure change curve over time in real time. Different ointment samples were coated inside the test cell, and CO2 gas was introduced into the test cell to 1 atm. The change in internal harmful gas pressure over time was monitored. Results are as follows: Figure 3 As shown, the gas absorption rate and capacity of the ointments in Examples 1-2 were significantly higher than those in the comparative example.

[0138] Fiber accelerated aging test: Fiber samples coated with different greases were placed in an environment of 85℃ and 1 atm of harmful gas for accelerated aging testing. After 1000 hours, the attenuation increment at 1535nm was measured. A schematic diagram of the fiber sample structure is shown below. Figure 1 As shown, it includes a hollow optical fiber 1 and a secondary coating layer 3, and the surface of the hollow optical fiber is coated with fiber paste 2 prepared in different embodiments and comparative examples, so that the fiber paste 2 fills the space between the hollow optical fiber 1 and the secondary coating layer 3.

[0139] Physical properties of ointments: Test method for dispersion stability: Seal an appropriate amount of ointment sample in a glass bottle and stand vertically in a constant temperature oven at 80℃ or 100℃ for 168 hours. After the test, qualitative evaluation is performed by visually observing whether the ointment is uniform and whether there is oil layer precipitation or particle sedimentation zone; at the same time, the stability of the ointment structure is quantitatively evaluated by comparing the dropping point and cone penetration of each sample (the test method is shown in YD / T 839.2-2014). This method is a key basis for predicting the long-term storage performance of ointments and verifying the dispersion stability of functional fillers (such as MOF) in the matrix.

[0140] Table 1. Performance test results of the fiber paste prepared in different examples and comparative examples.

[0141]

[0142] As shown in Table 1, the fiber attenuation increment of the coatings in Examples 1-2, 2-2, 3-2, and 4-2 was <0.05 dB / km, and the coatings were stable without precipitation. The fiber attenuation increment of the coatings in Comparative Example 1-2 was >0.2 dB / km. After long-term use of simple mechanical mixing with hydrophobically modified ZIF-8, the nanoparticles still agglomerated due to van der Waals forces, resulting in sedimentation. The fiber attenuation increment of the coating in Comparative Example 2-2 was >0.3 dB / km, proving that although the materials were initially forcibly dispersed, they were inherently incompatible and would re-agglomerate during subsequent processing or storage, leading to performance degradation and decreased stability. These agglomerates severely damaged the physical structure of the coatings. The experimental results of Comparative Example 3-2 and Comparative Example 4-2 both show that hydrophobic modification ensured that the dispersed particles could exist stably without re-agglomeration, while solvent dispersion ensured that a sufficient number of individual hydrophobic particles could be uniformly distributed in the matrix. Both are indispensable.

[0143] Table 1 demonstrates that the dropping point, cone penetration, and other indicators of the ointments in Examples 1-2, 2-2, 3-2, and 4-2 all meet the requirements of the YD / T 839.3-2014 standard.

[0144] The above results demonstrate that the fiber paste containing hydrophobically modified ZIF material and its preparation method provided by this invention effectively solve the problem of ZIF dispersion stability in the paste, endow the paste with excellent active gas absorption function, and provide a strong guarantee for the long-term reliability of optical fiber communication systems.

[0145] The hollow fiber optic cable provided by this invention can also be mixed with existing solid fiber optic cables to form a hybrid optical cable according to the needs of the application scenario. The solid fiber optic cable includes at least one solid fiber unit, and the solid fiber unit includes a loose tube and multiple solid fibers wrapped in the loose tube. The solid fibers can be G.652D, G.654E or G.655, etc.

[0146] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A gas-adsorption type fiber paste for hollow optical fibers, characterized in that, By weight, it includes 80-95 parts base oil, 5-15 parts thickener, 0.1-1 parts antioxidant, and 0.5-5 parts hydrophobically modified MOF material; The hydrophobically modified MOF material is a material synthesized by using hydrophobic molecules as co-ligands during the synthesis of the MOF material. The preparation method of the fiber paste includes the following steps: dispersing the hydrophobically modified MOF material in an organic solvent to form a MOF slurry, then mixing the slurry with the base oil, thickener and antioxidant evenly, and then removing the organic solvent by vacuum distillation to obtain the fiber paste.

2. The fiber cream as described in claim 1, characterized in that, The MOF material is one or more of the ZIFs series, UiOs series, and MILs series.

3. The fiber cream as described in claim 1, characterized in that, When the MOF material is a ZIFs series, the hydrophobic molecule is a hydrophobic imidazole molecule with 5-20 carbon atoms; When the MOF material is a UiOs series or a MILs series, the hydrophobic molecule is a hydrophobic alkyl carboxylic acid with 5-20 carbon atoms.

4. The fiber cream as described in claim 1, characterized in that, In the synthesis of the hydrophobically modified MOF material, the ligand corresponding to the MOF material is the first ligand, and the hydrophobic molecule is the second ligand. The molar ratio of the first ligand to the second ligand is (1-10):

1.

5. The fiber cream as described in claim 1, characterized in that, The base oil is a mineral oil, a synthetic hydrocarbon oil, or a mixture thereof; The thickener is polyisobutylene, hydrogenated styrene-butadiene copolymer, or a combination thereof; The antioxidant is one or more of phenolic antioxidants and phosphorus antioxidants.

6. The method for preparing the fiber paste according to any one of claims 1 to 5, characterized in that, The process includes the following steps: dispersing the hydrophobically modified MOF material in an organic solvent to form a MOF slurry; then mixing the slurry with the base oil, thickener, and antioxidant until homogeneous; and finally removing the organic solvent by vacuum distillation to obtain the fiber paste.

7. The preparation method according to claim 6, characterized in that, Specifically, the steps include the following: S1: The hydrophobically modified MOF material is dispersed in an organic solvent and then ultrasonically treated to form a uniform and stable MOF slurry; S2: The MOF slurry obtained in step S1 is added to the preheated base oil under stirring conditions to form a primary mixture; S3: Add the thickener and antioxidant to the primary mixture of step S2, and allow the thickener to fully swell under heating and stirring conditions to homogenize the system; S4: Remove the organic solvent from the mixture obtained in step S3 under reduced pressure and heating conditions; S5: The product obtained in step S4 is homogenized and vacuum degassed to obtain the fiber paste product.

8. The preparation method according to claim 7, characterized in that, The ultrasonic treatment in step S1 is ultrasonic fragmentation of the probe under ice-water bath cooling; and / or, In step S4, the heating temperature is 60-75℃, and the absolute pressure of the system is not higher than 15 kPa.

9. A hollow optical fiber cable, characterized in that, The optical fiber includes a hollow fiber and a secondary coating layer, and the surface of the hollow fiber is coated with a fiber paste as described in any one of claims 1 to 5, such that the fiber paste fills the space between the hollow fiber and the secondary coating layer. The hydrophobically modified MOF material contained in the fiber paste is a porous adsorbent material that can continuously adsorb harmful gases that permeate during the production and use of the optical cable, so as to prevent gas from penetrating into the optical fiber and causing optical fiber attenuation.

10. A hybrid optical cable, characterized in that, It is formed by a hybrid cable of hollow-core optical fiber cable and solid-core optical fiber cable, wherein the hollow-core optical fiber cable is the hollow-core optical fiber cable as described in claim 9; the solid-core optical fiber cable includes at least one solid-core optical fiber unit, the solid-core optical fiber unit includes a loose tube and multiple solid-core optical fibers wrapped in the loose tube, and the solid-core optical fibers are G.652D, G.654E or G.655.

Images