Gas adsorption type fiber paste for hollow-core optical fiber, optical cable and preparation method of gas adsorption type fiber paste

Abstract

The invention belongs to the technical field of optical fiber factice, and particularly relates to gas adsorption type fiber factice for a hollow-core optical fiber, an optical cable and a preparation method of the gas adsorption type fiber factice. The gas adsorption type fiber paste for the hollow-core optical fiber, provided by the invention, comprises the MOFs porous adsorption material with hydrophobic modification, and the introduction of the porous adsorption material can continuously adsorb infiltrated harmful gas in the optical cable production and use process, so that the gas is prevented from infiltrating into the optical fiber to cause attenuation of the optical fiber.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of optical fiber grease, more particularly, relates to a gas adsorption type fiber grease for hollow core optical fiber, an optical cable and a preparation method thereof. BACKGROUND

[0002] Hollow core optical fiber is an optical fiber based on microstructure photonic bandgap or anti-resonance principle, whose core is an air channel, which can significantly reduce nonlinear effects and delay, and is suitable for high-power laser transmission, low-delay communication and other fields. However, the hollow structure also brings key challenges. Due to its special structure, gas penetration problems may occur during production, cabling and use. External gases (such as H2O, CO2, CO) may penetrate into the hollow core optical fiber, causing light scattering and absorption loss, and increasing the attenuation of the optical fiber. Traditional sealing methods have limitations and rely on pure physical methods to seal the two ends of the optical fiber, such as fusion, glue sealing or end cap packaging, etc. However, high temperature and mechanical stress during the secondary coating process of the optical cable and other production processes can easily damage the sealing performance, leading to gas penetration. The current traditional sealing method cannot solve the problem of gas penetration during the production stage, especially the secondary coating stage. SUMMARY

[0003] In view of the defects of the prior art, the purpose of the present application is to provide an optical fiber grease (referred to as fiber grease) that can efficiently and durably absorb harmful gases, by introducing a specially modified MOFs material to solve the gas penetration problem of hollow core optical fiber.

[0004] To achieve the above-mentioned purpose, in a first aspect, the present application provides a gas adsorption type fiber grease for hollow core optical fiber, comprising 80-95 parts by mass of base oil, 5-15 parts by mass of thickening agent, 0.1-1 parts by mass of antioxidant and 0.5-5 parts by mass of hydrophobic modified MOF material. The hydrophobic modified MOF material is a material synthesized by using a hydrophobic molecule as a co-ligand during the synthesis of the MOF material.

[0005] Preferably, the MOF material is one or more of the ZIFs series, the UiOs series and the MILs series.

[0006] Preferably, when the MOF material is the ZIFs series, the hydrophobic molecule is a hydrophobic imidazole molecule with a carbon number of 5-20; when the MOF material is the UiOs series or the MILs series, the hydrophobic molecule is a hydrophobic alkyl carboxylic acid with a carbon number of 5-20.

[0007] Further preferably, the hydrophobic imidazole molecule is one or more of branched alkyl imidazole with a carbon number of 5-20, long-chain alkyl imidazole with a carbon number of 5-20, fluorine-containing imidazole with a carbon number of 5-20 and fluorine-containing ionic liquid with a carbon number of 5-20.

[0008] Preferably, in the synthesis process of the hydrophobically modified MOF material, the ligand corresponding to the MOF material is a first ligand, and the hydrophobic molecule is a second ligand, and the molar ratio of the first ligand to the second ligand is (1-10):1.

[0009] Another object of the present application is to provide a preparation method of the above-mentioned fiber paste, which solves the problems of agglomeration and dispersion stability of MOF in the ointment through innovative material modification and multi-stage dispersion process. The preparation method of the fiber paste comprises the following steps: dispersing the hydrophobically modified MOF material in an organic solvent to form an MOF slurry, then uniformly mixing the slurry with the base oil, thickening agent and antioxidant, and removing the organic solvent by vacuum distillation to obtain the fiber paste.

[0010] Preferably, the preparation method specifically comprises the following steps: S1: dispersing the hydrophobically modified MOF material in an organic solvent, and forming a uniform and stable MOF slurry by ultrasonic treatment; S2: adding the MOF slurry obtained in step S1 to preheated base oil under stirring to form a primary mixture; S3: adding the thickening agent and antioxidant to the primary mixture of step S2, and fully swelling the thickening agent under heating and stirring to homogenize the system; S4: removing the organic solvent from the mixture obtained in step S3 under reduced pressure and heating; S5: homogenizing and vacuum degassing the product obtained in step S4 to obtain the fiber paste product.

[0011] Further preferably, the ultrasonic treatment in step S1 is probe ultrasonic crushing under ice water bath cooling.

[0012] Further preferably, the heating temperature in step S4 is 60-75℃, and the absolute pressure of the system is not higher than 15 kPa.

[0013] According to another aspect of the present application, a hollow optical fiber cable is provided, which comprises a hollow optical fiber and a secondary coating layer, and the surface of the hollow optical fiber is coated with the fiber paste, so that the fiber paste is filled between the hollow optical fiber and the secondary coating layer, and the hydrophobically modified MOF material contained in the fiber paste is a porous adsorbent material, which can continuously adsorb harmful gases penetrating into the cable during production and use of the cable, and is used for preventing the penetration of gases into the optical fiber to cause attenuation of the optical fiber.

[0014] According to another aspect of the present application, there is also provided a hybrid optical cable formed by mixing a solid core optical fiber cable and the hollow core optical fiber cable described above, the solid core optical fiber cable comprising at least one solid core optical fiber unit, the solid core optical fiber unit comprising a loose tube and a plurality of solid core optical fibers wrapped by the loose tube, the solid core optical fibers being G.652D, G.654E or G.655.

[0015] Overall, compared with the prior art, the above technical solutions conceived by the present application have the following beneficial effects: (1) The gas adsorption type optical fiber grease for hollow core optical fiber provided by the present application contains MOF porous adsorbent with hydrophobic modification. The introduction of the porous adsorbent can continuously adsorb harmful gases that penetrate into the optical cable during production and use, thereby preventing the penetration of gases into the optical fiber and causing optical fiber attenuation.

[0016] (2) The present application initially attempts to introduce metal organic framework material MOF into the optical fiber grease in order to adsorb harmful gases by utilizing the porous adsorption property of MOF and thereby prevent the penetration of gases into the hollow core optical fiber. However, it is found in experiments that MOF is difficult to uniformly disperse in the grease when directly introduced. Therefore, the present application proposes to use hydrophobic imidazole molecules as co-ligands during the synthesis of MOF material to obtain MOF material with hydrophobic modification. The use of hydrophobic imidazole molecules as co-ligands changes the surface properties of metal organic framework material MOF at the molecular level, so that the MOF has intrinsic hydrophobicity and the compatibility with the grease matrix is fundamentally improved.

[0017] (3) In the preparation process of the gas adsorption type optical fiber grease of the present application, a multi-stage dispersion process of "first solvent dispersion and then solvent removal" is adopted, which effectively solves the problem of agglomeration of nano-MOF particles in high-viscosity grease and realizes the micro-uniform dispersion of MOF.

[0018] (4) Tests show that the gas adsorption type optical fiber grease for hollow core optical fiber provided by the present application has the following technical advantages: 1) high efficiency of gas absorption: the MOF material after hydrophobic modification maintains high specific surface area and microporous structure, and has excellent adsorption capacity and rate for harmful gases; 2) long-term stability: the MOF material after hydrophobic modification is stably dispersed in the grease without sedimentation and agglomeration, ensuring the persistence of gas adsorption performance; 3) good compatibility: does not affect the key physical indicators such as drop point and cone penetration of the original grease; 4) industrial value: provides a reliable active optical fiber harmful gas adsorption solution, the process is mature and suitable for large-scale production, which can significantly prolong the service life of the optical cable. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a structural schematic diagram of the hollow core optical fiber cable provided by the present application; Figure 2is the XRD diffraction pattern of the crystal before and after hydrophobic modification of ZIF-8 provided by the embodiment 1-1 of the present application; Figure 3 is the gas absorption performance test result of the fiber paste provided by the embodiment and the comparative example of the present application; In all the drawings, the same reference signs are used to indicate the same elements or structures, wherein: 1 - hollow core optical fiber; 2 - fiber paste; 3 - secondary coating layer. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0021] The present application aims at the gas permeation problem of hollow core optical fiber, and proposes a gas adsorption type fiber paste coated on the surface of the hollow core optical fiber in the secondary coating stage, which protects the optical fiber from the influence of gas permeation through the dual mechanisms of chemical adsorption and physical barrier. Metal organic framework materials (MOFs), such as ZIFs series, UiOs series and MILs series, especially ZIF series MOFs, have high specific surface area and regular microporous structure, and have good adsorption performance on the above-mentioned gases. However, there are the following technical bottlenecks in directly applying metal organic framework materials to the fiber paste: the MOF surface is hydrophilic, and has poor compatibility with the hydrophobic ointment matrix, and phase separation is easy to occur; the nano-scale MOF particles are easy to agglomerate in the viscous ointment, and are difficult to uniformly disperse, which seriously affects the gas absorption efficiency; the traditional mechanical mixing method cannot realize the nano-scale dispersion of MOF in the ointment, resulting in too high local concentration, which affects the physical properties of the ointment. Therefore, it is urgent to develop a new type of fiber paste which has excellent gas absorption performance and good dispersion stability.

[0022] Therefore, the present application provides a gas adsorption type fiber paste for hollow core optical fiber, which comprises, in terms of mass parts, 80-95 parts of base oil, 5-15 parts of thickening agent, 0.1-1 part of antioxidant and 0.5-5 parts of hydrophobically modified MOF material; the hydrophobically modified MOF material is a material synthesized by using a hydrophobic molecule as a co-ligand in the synthesis process of the MOF material. The present application proposes to synthesize the hydrophobically modified MOF material by using a hydrophobic imidazole molecule as a co-ligand in the synthesis process of the MOF material, and to use the hydrophobic imidazole molecule as a co-ligand to change the surface properties of the metal organic framework material MOF from the molecular level, so that it has intrinsic hydrophobicity, and the compatibility with the ointment matrix is fundamentally improved.

[0023] In some embodiments, the MOF material is one or more of 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.

[0024] In some embodiments, when the MOF material is ZIFs series, the hydrophobic molecule is a hydrophobic imidazole molecule with carbon number of 5-20, specifically including, but not limited to, one or more of branched alkyl imidazole with carbon number of 5-20 (more preferably carbon number of 10-15), long chain alkyl imidazole with carbon number of 5-20, fluorine-containing imidazole with carbon number of 5-20, and fluorine-containing ionic liquid with carbon number of 5-20; the hydrophobic imidazole molecule adopted by ZIFs series MOF is an imidazole molecule providing steric hindrance for hydrophobic modification of ZIFs series materials. In preferred embodiments, the hydrophobic imidazole molecule is one or more of 1-hexyl imidazole, 1-octyl imidazole, 1-dodecyl imidazole, 1-hexadecyl imidazole, 1-octadecyl imidazole, 1-hexyl-3-methyl imidazole (HMIM), 1-octyl-3-methyl imidazole (OMIM), 1-decyl-3-methyl imidazole (DMIM), 1-dodecyl-3-methyl imidazole (C12MIM), 1-hexadecyl-3-methyl imidazole, 1-benzyl imidazole, 1-(1-naphthylmethyl)imidazole, 1-trityl imidazole, 1-(perfluorohexyl)imidazole, 1-(1H,1H,2H,2H-perfluorooctyl)imidazole, 1-methyl-3-(1H,1H,2H,2H-perfluorooctyl)imidazole.

[0025] When the MOF material is UiOs series or MILs series, the hydrophobic molecule is a hydrophobic alkyl carboxylic acid with carbon number of 5-20 (more preferably carbon number of 10-15). For example, the main ligand of MIL-100 is trimesic 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.

[0026] In some embodiments, the hydrophobically modified MOF material is synthesized by using a first ligand and a second ligand, wherein the molar ratio of the first ligand to the second ligand is (1-10):1. The first ligand is the ligand corresponding to the MOF material, or the organic linker used in the synthesis of the MOF material, or the strut ligand as the main building block. For example, in the synthesis of ZIF-8, the first ligand is 2-methylimidazole, and the second ligand is hexyl imidazole, which is also used as a co-ligand in the synthesis of ZIF-8. The molar ratio of 2-methylimidazole to hexyl imidazole is (1-10):1.

[0027] The base oil, thickener, and antioxidant used in the present application are conventional components commonly used in ointments. In some embodiments, 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; and the antioxidant is one or more of a phenolic antioxidant and a phosphorus antioxidant.

[0028] The present application also provides a preparation method of the ointment, which comprises the following steps: dispersing the hydrophobically modified MOF material in an organic solvent to form a MOF slurry, then uniformly mixing the slurry with the base oil, thickener, and antioxidant, and removing the organic solvent by distillation under reduced pressure to obtain the ointment.

[0029] In some embodiments, the preparation method specifically comprises the following steps: S1: slurry preparation: dispersing the hydrophobically modified MOF material in an organic solvent, and forming a uniform and stable MOF slurry by ultrasonic treatment; S2: primary mixing: adding the MOF slurry obtained in step S1 to preheated base oil under stirring to form a primary mixture; S3: integration and shaping: adding the thickener and antioxidant to the primary mixture of step S2, and allowing the thickener to swell sufficiently under heating and stirring to homogenize the system; S4: solvent removal: removing the organic solvent from the mixture obtained in step S3 under reduced pressure and heating; S5: post-treatment: homogenizing and vacuum deaerating the product obtained in step S4 to obtain the ointment product.

[0030] In some embodiments, the organic solvent in step S1 is one or more of acetone, methyl ethyl ketone (MEK), N, N-dimethylformamide (DMF), and a mixture of ethanol. In some embodiments, the ultrasonic treatment in step S1 is probe sonication under ice water bath cooling. The probe sonication has high power (400-600W), and the heat generation is significant. The boiling point of acetone is low, and the ice water bath can control the reaction temperature, prevent solvent evaporation and excessive slurry temperature, avoid potential damage to the structure of ZIF-8, and ensure operation safety. The probe sonication directly transmits high-intensity ultrasonic energy to the inside of the sample solution, and the energy is concentrated, and the dispersion efficiency and effect are better.

[0031] In some embodiments, the heating temperature in step S4 is 60-75℃, and the absolute pressure of the system is not higher than 15 kPa, for example, 10 kPa to 15 kPa. This condition can further improve the solvent removal efficiency and optimize the product performance.

[0032] In the preparation of the ointment, the hydrophobically modified MOF material is dispersed in an organic solvent to form a slurry, and then mixed and dispersed with base oil, thickening agent and antioxidant, and finally distilled under reduced pressure to remove the organic solvent. This preparation method ingeniously solves the problem of agglomeration of nano-MOF particles in high-viscosity ointment, and realizes the micro-uniform dispersion of MOF.

[0033] The application also provides a hollow optical fiber cable, as shown in the figure, comprising a hollow optical fiber 1 and a secondary coating layer 3, and the surface of the hollow optical fiber is coated with the ointment 2 of the application, so that the ointment 2 is filled between the hollow optical fiber 1 and the secondary coating layer 3, and the hydrophobically modified MOF material contained in the ointment is a porous adsorbent material, which can continuously adsorb harmful gases penetrating in the production and use process of the optical cable (due to the unsealed treatment in the production process of the optical fiber, the adsorption of harmful gases in the production process is required more; in the normal use process, the optical fiber end side is sealed, and the requirement for the penetration of harmful gases is relatively small), which is used to prevent the penetration of gases into the optical fiber and cause the attenuation of the optical fiber. Figure 1

[0034] In some embodiments, the preparation of the hollow optical fiber cable comprises the following steps: coating the gas adsorption ointment on the surface of the hollow optical fiber; then performing the loose tube extrusion or armor process to form the cable structure; and continuously adsorbing the harmful gases penetrating in the production process of the optical cable through the porous adsorbent material in the ointment.

[0035] The hollow optical fiber cable of the application is suitable for high-power laser transmission, low-delay communication or quantum communication fields.

[0036] ​The application also provides a hybrid optical cable formed by mixing a hollow optical fiber cable and a solid optical fiber cable, wherein the hollow optical fiber cable can adopt the structure of the hollow optical fiber cable described above, and the solid optical fiber cable can include at least one existing solid optical fiber unit, the solid optical fiber unit including a loose tube and a plurality of solid optical fibers wrapped by the loose tube, and the solid optical fibers can be G.652D, G.654E or G.655, etc.

[0037] Embodiments of the present application are implemented on the premise of the technical solutions of the present application, and detailed implementation manners and processes are given, but the protection scope of the present application is not limited to the following embodiments. The process parameters not specified in the following embodiments are generally according to conventional conditions.

[0038] The endpoints of the ranges and any values described in this disclosure are not limited to the precise values stated. The ranges and values should be interpreted as approximations. The endpoints of the ranges and values are provided as a separate point for the convenience of the reader. The ranges and values are approximate values and can be combined with other ranges or values to form new ranges or values. These are only examples of ranges and values and are not intended to be limiting.

[0039] The process parameters not specified in the following embodiments are generally according to conventional conditions.

[0040] The embodiments of the present application are described below with reference to the accompanying drawings of the embodiments of the present application.

[0041] Example 1-1 Synthesis of hydrophobically modified ZIF-8: Take 2-methylimidazole (1.64 g, 20 mmol) and 1-hexylimidazole (0.62 g, 4 mmol) and dissolve them in 40 mL of methanol, marked as A solution; Take zinc nitrate hexahydrate (2.97 g, 10 mmol) and dissolve it in 40 mL of methanol, marked as B solution; Under stirring at room temperature, pour A solution into B solution quickly, and continue to stir for 24 hours; After the reaction is completed, centrifuge to collect the white precipitate, and wash it with methanol for 3 times; Dry the product in a vacuum drying oven at 80℃ for 12 hours to obtain hydrophobically modified ZIF-8 powder.

[0042] Comparative Example 1-1 Synthesis of common ZIF-8: Take 2-methylimidazole (1.64 g, 20 mmol) and dissolve it in 40 mL of methanol, marked as A solution; Zinc nitrate hexahydrate (2.97 g, 10 mmol) was weighed into 40 mL of methanol, and labeled as solution B; Solution A was quickly poured into solution B under stirring at room temperature, and the reaction was continued for 24 hours under stirring; After the reaction was completed, the white precipitate was collected by centrifugation and washed with methanol for 3 times; The product was dried in a vacuum oven at 80°C for 12 hours to obtain ZIF-8 powder.

[0043] The obtained organic framework material of the hydrophobically modified ZIF-8 of Example 1-1 and the ordinary ZIF-8 powder of Comparative Example 1-1 was characterized: BET test showed that the specific surface area of the material of Example 1-1 was 1600 m 2 / g, which was comparable to that of Comparative Example 1-1 (1650 m 2 / g), proving that the modification did not destroy the porous structure.

[0044] Water contact angle test showed that the contact angle of Example 1 material was 125°, while that of Comparative Example 1 was only 65°, proving that the hydrophobicity was significantly improved; XRD spectrum showed that the crystal structure of ZIF-8 before and after hydrophobic modification was consistent, proving that the modification was successful and the crystal framework of ZIF-8 was maintained, as shown in Figure 2 .

[0045] Example 1-2 Preparation of the paste: 2.0 g of the hydrophobically modified ZIF-8 prepared in Example 1-1 was dispersed in 50 mL of acetone, first sheared at 5000 rpm for 5 minutes, and then subjected to probe ultrasonic treatment (power 500 W, working for 2 seconds, intermittent for 3 seconds, total time 15 minutes) in an ice water bath to obtain a uniform slurry; 150 g of mineral oil (100SN) was placed in a 500 mL reaction bottle with stirring and heating, preheated to 50°C, and the above MOF slurry was slowly and uniformly added to the preheated base oil under stirring at 400 rpm, and stirring was continued for 30 minutes after the addition was completed to form a primary mixture; 20 g of polyisobutylene PIB (Daehwa, PB950) thickener and 0.5 g of antioxidant BHT were added to the primary mixture, and the temperature was raised to 80°C, the stirring speed was increased to 800 rpm, and the stirring was continued for 2 hours until the system was uniformly viscous; The reaction system was transferred to a reduced pressure distillation device, and distilled at 70°C and absolute pressure of 11.3 kPa for 1 hour until no distillate was distilled out; The obtained paste was ground by a three-roll grinder for 3 times, and then subjected to vacuum defoaming treatment to obtain the final paste product.

[0046] Comparative Example 1-2 Other than Example 1-2, except that 2.0 g of hydrophobically modified ZIF-8 was directly added into the base oil without solvent dispersion step, and the grease was prepared by the same procedure after mechanical stirring mixing, the specific preparation method is as follows: Take 150 g of mineral oil (100SN) into a 500 mL reaction bottle with stirring and heating, preheat to 50°C, under 400 rpm stirring, add 2.0 g of hydrophobically modified ZIF-8 prepared in Example 1-1, continue stirring for 30 minutes; 20 g of polyisobutylene PIB (Daehwa, PB950) thickener and 0.5 g of antioxidant BHT were added to the system, and the stirring speed was increased to 800 rpm. The system was stirred for 2 hours until it was uniform and viscous; The reaction system was transferred to a vacuum distillation device, and distilled at 65°C and -0.09 MPa for 1 hour until no distillate was distilled out; The obtained paste was ground by a three-roll grinder for 3 times, and then defoamed by a vacuum defoaming machine to obtain the final paste product.

[0047] Comparative Example 2-2 Other than Example 1-2, except that the hydrophobically modified ZIF-8 was replaced by the ordinary ZIF-8 material of Comparative Example 1-1.

[0048] Comparative Example 3-2 Other than Comparative Example 1-2, except that the hydrophobically modified ZIF-8 was replaced by the ordinary ZIF-8 material of Comparative Example 1-1.

[0049] Comparative Example 4-2 The ordinary grease was prepared without adding any ZIF material, and the preparation method was as follows: Take 150 g of mineral oil (100SN) into a 500 mL reaction bottle with stirring and heating, preheat to 50°C; 20 g of polyisobutylene PIB (Daehwa, PB950) thickener and 0.5 g of antioxidant BHT were added to the system, and the stirring speed was increased to 800 rpm. The system was stirred for 2 hours until it was uniform and viscous; The reaction system was transferred to a vacuum distillation device, and distilled at 65°C and -0.09 MPa for 1 hour until no distillate was distilled out; The obtained paste was ground by a three-roll grinder for 3 times, and then defoamed by a vacuum defoaming machine to obtain the final paste product.

[0050] Example 2-1 Other than Example 1-1, except that the ZIF material is ZIF-67. The specific preparation method is as follows: Synthesis of hydrophobically modified ZIF-67: Take 2-methylimidazole (1.64 g, 20 mmol) and 2-ethyl-4-methylimidazole (0.44 g, 4 mmol) and dissolve them in 40 mL of methanol, marked as A liquid; Take the cobalt nitrate hexahydrate (2.91 g, 10 mmol) and dissolve it in 40 mL of methanol, marked as B liquid; Under stirring at room temperature, pour A liquid into B liquid quickly, continue to stir for 24 hours; After the reaction is completed, centrifugal collection is performed on the white precipitate, and methanol is used for washing 3 times; The product is dried in a vacuum drying oven at 80°C for 12 hours to obtain hydrophobically modified ZIF-67 powder.

[0051] Example 2-2 Disperse 2.0 g of hydrophobically modified ZIF-67 prepared in Example 2-1 in 50 mL of acetone, first disperse at 5000 rpm for 5 minutes, then perform probe ultrasonic treatment (power 500 W, work for 2 seconds, intermittent 3 seconds, total time 15 minutes) in an ice water bath to obtain a uniform slurry; Take 150 g of mineral oil (100SN) and place it in a 500 mL reaction bottle with stirring and heating, preheat to 50°C, under 400 rpm stirring, slowly and uniformly drop the above MOF slurry into the preheated base oil, continue to stir for 30 minutes after the dropping is completed, to form a primary mixture; Add 20 g of polyisobutylene PIB (Daehwa, PB950) thickener and 0.5 g of antioxidant BHT to the primary mixture, increase the stirring speed to 800 rpm, continue to stir for 2 hours until the system is uniformly viscous; The reaction system is transferred to a reduced pressure distillation device, and distilled at 65°C and absolute pressure of 12 kPa for 1 hour until no distillate is distilled out; The obtained paste is ground 3 times by a three-roll grinder, and then deaerated by a vacuum deaerator to obtain the final paste product.

[0052] Example 3-1 Preparation of hydrophobically modified UiO-66 gas adsorption material.

[0053] Take 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, marked as A liquid; Zirconium tetrachloride (1.87 g, 8 mmol) was weighed into 40 mL of N, N- dimethylformamide, labeled as B solution; A solution was quickly poured into B solution under stirring at room temperature, followed by the addition of 1.5 mL of concentrated hydrochloric acid, and the reaction was continued to stir for 24 hours; after the reaction should be completed, the white precipitate was collected by centrifugation and washed with DMF and methanol for 3 times respectively; The product was dried in a vacuum oven at 120°C for 12 hours to obtain the hydrophobically modified UiO-66 powder.

[0054] Example 3-2 The hydrophobically modified UiO-66 gas adsorbent material was dispersed in a mixed solvent of N, N-dimethylformamide (DMF) and ethanol, first dispersed at a high speed of 5000 rpm for 5 minutes, and then treated with a probe ultrasonic (power 500W, working for 2 seconds, intermittent for 3 seconds, total time 15-30 minutes) in an ice water bath to form a uniform and stable MOF slurry; 150 g of mineral oil (100SN) was taken into a 500 mL reaction bottle with stirring and heating, preheated to 50°C, and the above MOF slurry was slowly and uniformly added into the preheated base oil under stirring at 400 rpm, and after the addition was completed, the stirring was continued for 30 minutes to form a primary mixture; 20 g of thickener (hydrogenated styrene-butadiene block copolymer, Baling Petrochemical SEPS YH-4010, styrene content 37%) and 0.5 g of antioxidant BHT were added into the primary mixture, the temperature was raised to 80°C, the stirring speed was increased to 800 rpm, and the stirring was continued for 2 hours until the system was uniformly viscous; The reaction system was transferred to a vacuum distillation device, and distilled at 70°C and absolute pressure of 11.5 kPa for 1 hour until no distillate was distilled out; The obtained paste was ground by a three-roll grinder for 3 times, and then treated by a vacuum defoaming machine to obtain the final paste product.

[0055] Example 4-1 Synthesis of hydrophobically modified MIL-100 (Fe).

[0056] Trimesic acid (0.840 g, 4 mmol) and dodecanoic acid (0.080 g, 0.4 mmol) were weighed into 40 mL of deionized water, labeled as A solution; Iron nitrate nonahydrate (1.616 g, 4 mmol) was weighed into 40 mL of deionized water, labeled as B solution; A solution was quickly poured into B solution under stirring at room temperature, and the reaction was continued to stir for 24 hours; after the reaction was completed, the orange-brown precipitate was collected by centrifugation and washed with hot water and ethanol for 3 times respectively; The product was dried in a vacuum oven at 120°C for 12 hours to obtain the hydrophobically modified MIL-100(Fe) powder.

[0057] Example 4-2 The hydrophobically modified MIL-100(Fe) gas adsorption material was dispersed in a mixed solvent of N,N-dimethylformamide (DMF) and ethanol, first dispersed at high speed for 5 minutes at 5000 rpm, and then probe ultrasonic treatment (power 500W, working for 2 seconds, intermittent for 3 seconds, total time 15-30 minutes) was carried out in an ice water bath to form a uniform and stable MOF slurry; 150 g of mineral oil (100SN) was taken into a 500 mL reaction bottle with stirring and heating, preheated to 50°C, and the above MOF slurry was slowly and uniformly added to the preheated base oil under stirring at 400 rpm, and stirring was continued for 30 minutes after the addition was completed to form a primary mixture; 20 g of thickener (hydrogenated styrene-butadiene block copolymer, Balin Petrochemical SEPSYH-4010, styrene content 37%) and 0.5 g of antioxidant BHT were added to the primary mixture, the temperature was raised to 80°C, the stirring speed was increased to 800 rpm, and stirring was continued for 2 hours until the system was uniformly viscous; The reaction system was transferred to a vacuum distillation device, and distilled at 70°C and an absolute pressure of 14 kPa for 1 hour until no distillate was distilled out; The obtained paste was ground by a three-roll grinder for 3 times, and then defoaming treatment was carried out by a vacuum defoaming machine to obtain the final paste product.

[0058] Performance test and effect verification: Dispersion stability test: The greases prepared by example 1-2 (hydrophobically modified ZIF-8 + solvent dispersion), comparative example 1-2 (hydrophobically 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 a graduated cylinder with a plug, and were left to stand at room temperature for 30 days. The results showed that the grease of example 1-2 had no obvious stratification and sedimentation, while the greases of comparative examples 1-2, 2-2 and 3-2 had obvious MOF sedimentation layer at the bottom.

[0059] Gas absorption performance test: A special test cell (a closed, constant volume reaction system that can accurately monitor the internal pressure changes caused by the absorption of gas by the ointment. The test cell contains a fixed sample tray to ensure that all ointment samples can be tested with the same exposed surface area and coating thickness. During testing, air, water vapor and other gas interference are removed, a high-precision, fast-response pressure sensor is connected, and a data acquisition system is used to record the pressure-time curve in real time) was prepared. Different ointment samples were coated in the test cell, and CO2 gas was filled into the test cell to 1 atm, and the internal harmful gas pressure change over time was monitored. The results are shown in Figure 3 As shown, the gas absorption rate and capacity of the ointments of Examples 1-2 were significantly higher than those of the comparative examples.

[0060] Optical fiber accelerated aging experiment: The optical fiber samples coated with different ointments were placed in an environment of 85°C and 1 atm of harmful gas for accelerated aging test. After 1000 hours, the attenuation increment of the optical fiber at 1535 nm was measured. The structure of the optical fiber sample is shown in Figure 1 As shown, it includes a hollow core optical fiber 1 and a secondary coating layer 3, and the surface of the hollow core optical fiber is coated with different ointments 2 prepared by the examples and comparative examples, so that the ointment 2 is filled between the hollow core optical fiber 1 and the secondary coating layer 3.

[0061] Ointment physical properties: test method for dispersion stability: seal an appropriate amount of ointment sample in a glass bottle and vertically stand in a constant temperature oven at 80°C or 100°C for 168 hours. After the test is completed, visually observe whether the ointment is uniform, whether the oil is eluted or the particles are settled, and make a qualitative judgment; at the same time, by comparing the dropping point and coning degree (see YD / T 839.2-2014 for detection method), the stability of the ointment structure is quantitatively evaluated. This method is a key basis for predicting the long-term storage performance of ointment and verifying the dispersion stability of functional fillers (such as MOF) in the matrix.

[0062] Table 1 Performance test results of ointments prepared by different examples and comparative examples

[0063] As can be seen from Table 1, the optical fiber attenuation increments of the greases coated with examples 1-2, 2-2, 3-2 and 4-2 are all <0.05 dB / km, and the greases are stable without precipitation; the optical fiber attenuation increment of the grease of comparative example 1-2 is >0.2 dB / km, and the ZIF-8 modified by hydrophobicity is only mechanically mixed, and the nanoparticles will still be agglomerated due to van der Waals force after a long time, and precipitation will occur; the optical fiber attenuation increment of the grease of comparative example 2-2 is >0.3 dB / km, which proves that although the material is forced to be dispersed at the beginning, the material is essentially incompatible, and re-agglomeration will occur during subsequent processing or storage, resulting in performance attenuation and stability decline, and these agglomerates seriously damage the physical structure of the grease; the experimental results of comparative examples 3-2 and 4-2 prove that hydrophobic modification ensures that the dispersed particles can exist stably without re-agglomeration; solvent dispersion ensures that there are enough single hydrophobic particles uniformly distributed in the matrix, and both are indispensable.

[0064] Table 1 proves that the drop point, cone penetration and other indicators of the greases of examples 1-2, 2-2, 3-2 and 4-2 all meet the requirements of the YD / T 839.3-2014 standard.

[0065] The above results prove that the grease containing hydrophobic modified ZIF material and the preparation method thereof provided by the application effectively solve the dispersion stability problem of ZIF in the grease, and endow the grease with excellent active gas absorption function, thereby providing a strong guarantee for the long-term reliability of the optical fiber communication system.

[0066] The hollow core optical fiber cable provided by the application can also be mixed with an existing solid core optical fiber cable to form a hybrid optical cable according to the needs of an application scene, the solid core optical fiber cable comprising at least one solid core optical fiber unit, and the solid core optical fiber unit comprising a loose tube and a plurality of solid core optical fibers wrapped by the loose tube, and the solid core optical fibers can be G.652D, G.654E or G.655, etc.

[0067] The above is only a specific embodiment of the application, but the protection scope of the application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the application, which should be covered within the protection scope of the application. Therefore, the protection scope of the application should be subject to the protection 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.

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 involves 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