A high transmission rate optical cable with low attenuation characteristics and a method of manufacturing the same

Abstract

The application discloses a high-transmission-rate optical cable with low attenuation characteristics and a preparation method thereof, belongs to the technical field of optical cable communication, and aims to solve the technical problem that the transmission performance and mechanical performance of the optical cable in the prior art need to be further improved, and specifically comprises optical fibers, loose tubes, insulation layers and sheath layers which are sequentially arranged from inside to outside, gaps are left between the optical fibers and the loose tubes, and the gaps are filled with ointment, the polytetrafluoroethylene is filled with modified graphene and molybdenum disulfide, the mechanical performance and environmental adaptability of the optical cable are effectively improved, and the transmission speed of the optical cable is effectively improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of optical cable preparation, in particular to a high-transmission-rate optical cable with low attenuation characteristics and a preparation method thereof. BACKGROUND

[0002] In today's era of rapid development of digital information, the demand for high-transmission-rate optical cables with low attenuation characteristics is extremely urgent. With the vigorous rise of new infrastructures such as 5G, data centers, computing power networks and the Internet of Things, the optical fiber communication network as the'supporting base' of these facilities faces higher performance requirements in terms of capacity, distance and delay. New optical fiber technologies such as ultra-low-loss optical fiber, space division multiplexing optical fiber and hollow core optical fiber are emerging, among which the ultra-low-loss optical fiber has entered the stage of commercialization, helping the development of optical transmission systems towards ultra-high speed, large capacity and long distance.

[0003] In the prior art, the structure of the optical cable mainly comprises an optical fiber, a loose tube, an insulation layer and a sheath layer. The optical cable is usually used in multiple scenes such as underground pipelines, overhead and submarine laying. The environment is complex and difficult to predict, so the sheath layer of the optical cable needs to have strict requirements. The sheath layer of the optical cable is prone to be flattened or stretched and deformed, and the mechanical properties are not excellent enough. The optical fiber is deformed or broken under stress, causing signal transmission attenuation. After the optical cable is used for a period of time, the sheath is broken and the optical fiber is pierced out, causing damage to the structure of the optical cable and line failure problems. At the same time, during the construction and line operation process, due to factors such as wind force and artificial external force, the optical cable is twisted and cracked, causing serious attenuation of the optical cable. Therefore, the transmission rate and mechanical properties of the optical cable need to be improved on the basis of the prior art. SUMMARY

[0004] The application aims to provide a high-transmission-rate optical cable with low attenuation characteristics and a preparation method thereof, and solve the technical problem that the transmission performance and mechanical properties of the optical cable in the prior art need to be further improved.

[0005] The application can achieve the above-mentioned purpose by the following technical scheme: a high-transmission-rate optical cable with low attenuation characteristics, which comprises an optical fiber, a loose tube, an insulation layer and a sheath layer arranged in sequence from inside to outside. A gap is left between the optical fiber and the loose tube, and the gap is filled with ointment.

[0006] The sheath layer comprises the following components by weight: 60-70 parts of high-pressure low-density polyethylene, 30-40 parts of modified polytetrafluoroethylene, 10-20 parts of random copolymerized polypropylene and 3-5 parts of auxiliary additives.

[0007] The preparation method of the modified polytetrafluoroethylene comprises the following steps:

[0008] A1, the modified graphene, molybdenum disulfide and anhydrous ethanol are mixed and added into a ball mill for ball milling dispersion for 8-12h, after the ball milling is completed, the ball milling slurry is transferred to a beaker, polyethylene glycol is added, and stirring is performed for 30-40min to obtain a mixed slurry;

[0009] A2, the pretreated polytetrafluoroethylene is added into a mixer, low-speed stirring is performed for 1-2min, the mixed slurry is added, stirring is performed for 10-20min, and then the mixed material is transferred to a 60-80℃ vacuum drying box for drying to constant weight to obtain modified polytetrafluoroethylene.

[0010] The synthesis mechanism of the modified polytetrafluoroethylene is as follows:

[0011] The mechanical force of the ball mill breaks the agglomerates of the modified graphene and molybdenum disulfide, meanwhile, the anhydrous ethanol acts as a medium, the fillers are uniformly dispersed in the liquid phase through shear force and impact force, the long-chain molecules of the polyethylene glycol are adsorbed on the surface of the fillers to form an oil-wet and water-repellent interface layer, thereby reducing the van der Waals attractive force between the fillers and preventing re-agglomeration; meanwhile, the hydroxyl groups of the polyethylene glycol can form a weak interaction with the molecular chain of the polytetrafluoroethylene, after the mixed slurry is added, the uniformly dispersed modified graphene and molybdenum disulfide are embedded into the polytetrafluoroethylene matrix through mechanical stirring force to form a filler-matrix composite system.

[0012] Further, the optical fiber is made of high-purity quartz glass, the loose tube is composed of polypropylene material or nylon material, the insulation layer is made of poly-p-phenyleneterephthalamide, and the auxiliary additive is composed of ultraviolet absorber, antioxidant, plasticizer and lubricant in a weight ratio of 1:0.8:4:0.8.

[0013] Further, in step A1, the weight ratio of the modified graphene, molybdenum disulfide, anhydrous ethanol and polyethylene glycol is 1:1:40:0.01-0.02.

[0014] The amount ratio is 1g:3g:40mL:0.01-0.02g, and the type of polyethylene glycol is PEG-400.

[0015] Further, in step A2, the weight ratio of the pretreated polytetrafluoroethylene and the mixed slurry is 4:1.

[0016] Further, the treatment method of the pretreated polytetrafluoroethylene is as follows: the polytetrafluoroethylene and low-molecular-weight polytetrafluoroethylene are added into a ball mill for ball milling for 2-4h, the ball-milled polytetrafluoroethylene is added into a sodium-naphthalene complex solution under nitrogen protection, the temperature is increased to 35-45℃, and after reaction for 20-30min, the polytetrafluoroethylene is washed to neutral with deionized water, then the KH560 ethanol solution is added, ultrasonic treatment is performed for 60-80min, and centrifugal drying is performed to obtain the pretreated polytetrafluoroethylene.

[0017] The synthesis mechanism of the pretreated polytetrafluoroethylene is as follows:

[0018] Naphthalene loses an electron under the action of sodium to generate naphthalene sodium radical anion, and the naphthalene ring of naphthalene sodium acts as a nucleophile to attack the C-F bond on the surface of polytetrafluoroethylene, resulting in the breaking of the C-F bond to generate C-Na + The intermediate is combined with the naphthalene ring to form etched polytetrafluoroethylene, the methoxy group of KH560 is hydrolyzed to generate a silanol group, and the silanol group is condensed with the active C site introduced on the surface of the polytetrafluoroethylene after sodium-naphthalene treatment to form a silicon-oxygen-carbon covalent bond, thereby fixing the KH560 on the surface of the polytetrafluoroethylene.

[0019] Further, the use amount ratio of the polytetrafluoroethylene, the low-molecular-weight tetrafluoroethylene, the sodium-naphthalene complex solution, and the KH560 ethanol solution is 100 g:0.1-0.5 g:1000 mL:500 mL; the sodium-naphthalene complex solution is composed of naphthalene, sodium, and tetrahydrofuran in a use amount ratio of 0.2 g:0.5 g:50 mL; and the KH560 ethanol solution is composed of γ-glycidyloxypropyltrimethoxysilane, ethanol, and water in a volume ratio of 1:8:1.

[0020] Further, in step A1, the preparation method of the modified graphene is as follows:

[0021] B1, the flake graphite, concentrated sulfuric acid and potassium permanganate are added into a beaker and uniformly mixed, the beaker is transferred to a constant-temperature water bath, the temperature is increased to 30-40 DEG C, and stirring is performed for 1-2 h, then the temperature is increased to 50-60 DEG C, and stirring is continued for 2-3 h, after the reaction is completed, filtration, washing and drying are performed, and the expanded graphite is obtained by heating and expanding;

[0022] B2, the concentrated sulfuric acid and the sodium nitrate are uniformly mixed in a beaker, and then the expanded graphite is added, stirring is performed for 15-20 min, the temperature is controlled to be 20-30 DEG C, the potassium permanganate is added, and the reaction is performed for 1-2 h, deionized water is added, the temperature is increased to 40-50 DEG C, and the 30wt% hydrogen peroxide solution is added until the color of the solution changes from brownish to bright yellow, and then filtration, washing and drying are performed to obtain the oxidized graphite;

[0023] B3, the oxidized graphite and deionized water are added into a beaker and ultrasonically treated at room temperature for 1-2 h, the pH is adjusted to 6.5-7.5 by using saturated ammonia water, and then the hydrazine hydrate is added, and the reaction system is placed in a 60-80 DEG C water bath and reacted for 2-4 h, and then the modified graphene is obtained after post-treatment.

[0024] The synthesis mechanism of the modified graphene is as follows:

[0025] After concentrated sulfuric acid and potassium permanganate are contacted with flake graphite, hydrogen ions and sulfate ions are inserted into the graphite interlayer by ion exchange to form a graphite intercalation compound, and meanwhile, the potassium permanganate releases active oxygen under the acidic condition to oxidize carbon atoms at the edges and defects of the graphite to generate functional groups such as carboxyl and hydroxyl, weaken the interlayer van der Waals force, expand the interlayer spacing, and after drying and heating, the intercalation in the interlayer is decomposed to form loose and porous expanded graphite; the expanded graphite is added into a mixed solution of concentrated sulfuric acid and sodium nitrate, the sodium nitrate is dissociated into nitrate ions in the concentrated sulfuric acid to form a strong oxidation system together with the potassium permanganate, further oxidize carbon atoms in the graphite layer to introduce a large number of epoxy and hydroxyl groups, and part of the edges form carboxyl groups; in the oxidation process, the hydrophilicity of the functional groups causes the graphite interlayer to adsorb water molecules to produce swelling, and meanwhile, mechanical stirring and the insertion of the oxidizing agent destroy the interlayer binding force to make the graphite layer gradually exfoliate into single-layer or few-layer oxidized graphite; hydrazine hydrate as a reducing agent reacts with the functional groups such as epoxy and hydroxyl on the surface of the oxidized graphite to release nitrogen and generate water molecules, break the C-O bond, and gradually restore the sp 2 Conjugated structure of graphene.

[0026] Further, in step B1, the amount ratio of the flake graphite, concentrated sulfuric acid and potassium permanganate is 2g:10mL:1g; the heating expansion step is that: after the dried graphite powder is ground, it is placed in a muffle furnace and heated to 800-1000℃ at a heating rate of 5-10℃ / s, and kept for 1-2min to obtain expanded graphite; in step B2, the amount ratio of the concentrated sulfuric acid, sodium nitrate, expanded graphite, potassium permanganate and deionized water is 50mL:1g:5g:7.5g:100mL; in step B3, the amount ratio of the oxidized graphite, deionized water and hydrazine hydrate is 1g:200mL:1-2mL, and the post-treatment step includes: after the reaction is completed, the mixed solution is transferred to a centrifuge tube for centrifugation, the lower liquid is washed with deionized water for 3-5 times, and then transferred to a 40-60℃ vacuum drying box for drying to constant weight to obtain modified graphene.

[0027] The application further provides a preparation method of the high-transmission-rate optical cable.

[0028] S1, high-pressure low-density polyethylene, modified polytetrafluoroethylene and random copolymerized polypropylene are mixed in a mixing machine, the temperature is raised to 280-320℃, auxiliary additives are added and uniformly mixed to obtain a premix;

[0029] S2, the premix is melt-extruded outside the insulation layer in a double-screw extruder, and after cooling and shaping, a sheath layer is obtained, and the high-transmission-rate optical cable is prepared.

[0030] Further, in step S1, the temperatures of the six temperature zones of the twin-screw extruder from the feeding end to the discharging end are 80-120 DEG C, 150-200 DEG C, 220-280 DEG C, 280-320 DEG C, 250-300 DEG C and 280-320 DEG C, respectively.

[0031] The application has the following advantages:

[0032] 1、The application is through the cladding of the cladding layer and the buffer layer to the optical fiber core, which can prevent the fiber core from being damaged by stress when the optical cable is laid or bent, avoid the attenuation of optical signals due to the destruction of the fiber core structure, the quartz cladding has excellent point chemical stability and thermal stability, which can keep the refractive index stable under high temperature and low temperature conditions, avoid the performance reduction of the cladding due to environmental changes, and affect the long-term transmission quality of high-speed signals; the combination of the cladding and the buffer layer makes the coating uniformly adhere to form a tight protective structure, and improves the long-distance low-delay transmission efficiency of high-speed optical signals.

[0033] 2、The application is through adding polytetrafluoroethylene in the cable material, which has high heat resistance and weather resistance, can resist the heat accumulation of the optical cable due to current or signal loss at high transmission rate, avoid the softening, deformation or aging of the cable material due to high temperature, ensure the stable operation of the optical cable in high temperature environment, and reduce the structural damage caused by temperature fluctuation; the modified polytetrafluoroethylene combines with fillers such as graphene and molybdenum disulfide, the two-dimensional sp2 hybrid carbon atoms of graphene form a highly conjugated pi electron system, when uniformly dispersed in the polytetrafluoroethylene matrix, the pi electron cloud of graphene can weaken the dipole orientation polarization of the polytetrafluoroethylene molecular chain through the electronic shielding effect, reduce the dielectric constant and dielectric loss, thereby reducing signal attenuation and improving transmission rate, at the same time, the d-orbital electrons of molybdenum disulfide are delocalized in the layer, but the interlayer electron transfer is limited, forming a dielectric barrier, when dispersed in polytetrafluoroethylene, the layered structure can be arranged in the direction of the electric field, forming a similar dielectric nanolayer, hindering the charge migration and reducing the leakage current, at the same time, the interlayer gap can reduce the orientation polarization of the polar CF2 group, further reducing the dielectric loss, that is, under the synergistic cooperation of modified graphene and molybdenum disulfide, the transmission rate of the optical cable is improved.

[0034] 3、The modified graphene has a two-dimensional sheet structure, a large specific surface area, and oxygen-containing functional groups on the surface that can form hydrogen bonds or van der Waals forces with polytetrafluoroethylene molecular chains. This strong interface bonding can effectively transfer stress and avoid interface debonding when the composite material is subjected to external force, thereby improving the overall mechanical strength. The graphene sheet layer acts as a heterogeneous nucleation site, promoting the formation of more and smaller polytetrafluoroethylene grains and reducing defects in large-size crystalline regions, thereby improving the elongation at break and tensile strength of the material. The strong interface bonding between the graphene sheet layer and the polytetrafluoroethylene molecular chains can provide a certain buffer space at low temperatures. When the material is subjected to cold shrinkage, the interaction between the sheet layer and the molecular chains can absorb stress and prevent cracks from occurring. Moreover, the modified graphene can hinder the ordered arrangement of molecular chains, reducing the degree of crystallinity and increasing the proportion of amorphous regions. The molecular chains in the amorphous regions remain flexible at low temperatures, thereby improving the environmental adaptability of the material. DETAILED DESCRIPTION

[0035] The technical solutions of the present application will be described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0036] In the present application, the polytetrafluoroethylene is from Shanghai Maikelin Biochemical Technology Co., Ltd., with a CAS number of 9002-84-0 and a refractive index of 1.37 (20℃);

[0037] In the present application, KH-560 is γ-glycidoxypropyltrimethoxysilane from Shanghai Xinyu Biological Technology Co., Ltd., with a CAS number of 2530-83-8 and a boiling point of 290℃;

[0038] In the present application, antioxidant 1010 is from Tianjin Li'anlong New Material Co., Ltd., with a CAS number of 6683-19-8 and a boiling point of 779.1℃;

[0039] In the present application, ultraviolet absorber UV-326 is from Wuhan Xingzhongcheng Technology Co., Ltd., with a CAS number of 3896-11-5;

[0040] In the present application, polyethylene glycol is from Nantong Chenrun Chemical Co., Ltd., with a CAS number of 25322-68-3 and a density of 1.27 g / cm³.

[0041] Example 1

[0042] The present embodiment provides a preparation method of a sheath layer premix for a high transmission rate optical cable with low attenuation characteristics, comprising the following steps:

[0043] S1, preparing modified graphene

[0044] Weigh: 10 g of flake graphite, 50 mL of concentrated sulfuric acid and 4 g of potassium permanganate into a beaker and mix well, transfer the beaker to a constant temperature water bath, the temperature is raised to 30℃, stirring for 1h, then the temperature is raised to 50℃, continue to stir for 2h, after the reaction is completed, cool to room temperature, add 100 mL of deionized water to the system, suction filtration, the filter cake is washed to neutral with deionized water, then transferred to a 60℃ vacuum drying oven and dried to constant weight, the dried graphite powder is ground and placed in a muffle furnace, heated to 800℃ at a heating rate of 5℃ / s, and kept for 1 min to obtain expanded graphite;

[0045] Weigh: 50 mL of concentrated sulfuric acid and 1 g of sodium nitrate are mixed well in a beaker, then 5 g of expanded graphite is added, stirred for 15 min, the temperature is controlled at 20℃, 7.5 g of potassium permanganate is added, reacted for 1h, 100 mL of deionized water is added, heated to 40℃, 30wt% hydrogen peroxide solution is added until the solution color changes from brown to bright yellow, after the reaction is completed, cool to room temperature, suction filtration, the filter cake is washed to neutral with deionized water, then transferred to a 60℃ vacuum drying oven and dried to constant weight to obtain oxidized graphite;

[0046] Weigh: 5 g of oxidized graphite, 1000 mL of deionized water is added to a beaker and ultrasonicated at room temperature for 1h, adjust the pH to 7 with saturated ammonia water, add 5 mL of hydrazine hydrate, and place the reaction system in a 60℃ water bath and react for 2h, after the reaction is completed, transfer the mixture to a centrifuge tube, wash the lower liquid with deionized water 3 times, then transfer to a 40℃ vacuum drying oven and dry to constant weight to obtain modified graphene.

[0047] S2, preparation of modified tetrafluoroethylene

[0048] Weigh: 10 g of modified graphene, 30 g of molybdenum disulfide and 400 mL of anhydrous ethanol are mixed and added to a ball mill for 8h of ball milling, after the ball milling is completed, the ball milling slurry is transferred to a beaker, 0.1 g of polyethylene glycol is added, stirred for 30-40 min to obtain a mixed slurry;

[0049] Weigh: 40 g of polytetrafluoroethylene and 2 g of low molecular weight polytetrafluoroethylene are added to a ball mill and ball milled for 2h, the ball milled polytetrafluoroethylene is added to a 400 mL sodium-naphthalene complex solution under nitrogen protection, the temperature is raised to 35℃, reacted for 20 min, washed to neutral with deionized water, then 200 mL of KH560 ethanol solution is added, ultrasonicated for 60 min, centrifuged, and placed in a 60℃ vacuum drying oven and dried to constant weight to obtain pretreated polytetrafluoroethylene;

[0050] Weighing: 40 g of pretreated polytetrafluoroethylene is added to a mixer, stirred at low speed for 1 min, then the mixed slurry is added, stirred for 10 min, and then the mixture is transferred to a 60℃ vacuum drying oven for drying to constant weight to obtain modified polytetrafluoroethylene.

[0051] S3, preparing a sheath layer premix

[0052] The ultraviolet absorber UV-326, the antioxidant 1010, the dioctyl adipate, and the calcium stearate are mixed in a weight ratio of 1:0.8:4:0.8 to obtain an auxiliary additive, which is ready for use.

[0053] Weighing: 60 parts of high-pressure low-density polyethylene, 30 parts of modified polytetrafluoroethylene, 10 parts of random copolymerized polypropylene, and the auxiliary additive are placed in a mixer to mix to obtain a sheath layer premix.

[0054] Example 2

[0055] The present embodiment provides a preparation method of a sheath layer premix for a high transmission rate optical cable with low attenuation characteristics, comprising the following steps:

[0056] S1, preparing modified graphene

[0057] Weighing: 10 g of flake graphite, 50 mL of concentrated sulfuric acid, and 4 g of potassium permanganate are added to a beaker and mixed uniformly, the beaker is transferred to a constant temperature water bath, the temperature is raised to 35℃, and stirring is performed for 1.5 h, then the temperature is raised to 55℃, and stirring is continued for 2.5 h, after the reaction is completed, the system is cooled to room temperature, 100 mL of deionized water is added, suction filtration is performed, the filter cake is washed with deionized water until it is neutral, then it is transferred to a 70℃ vacuum drying oven and dried to constant weight, the dried graphite powder is ground and placed in a muffle furnace, heated to 900℃ at a heating rate of 8℃ / s, and held for 1 min to obtain expanded graphite.

[0058] Weighing: 50 mL of concentrated sulfuric acid and 1 g of sodium nitrate are mixed uniformly in a beaker, then 5 g of expanded graphite is added, stirring is performed for 17 min, the temperature is controlled at 25℃, 7.5 g of potassium permanganate is added, and the reaction is performed for 1.5 h, then 100 mL of deionized water is added, the temperature is raised to 45℃, and 30 wt% hydrogen peroxide solution is added until the solution color changes from brownish to bright yellow, after the reaction is completed, the system is cooled to room temperature, suction filtration is performed, the filter cake is washed with deionized water until it is neutral, then it is transferred to a 70℃ vacuum drying oven and dried to constant weight to obtain oxidized graphite.

[0059] Weighing: 5g of graphite oxide, 1000mL of deionized water is added to a beaker and ultrasonic at room temperature for 1.5h, adjust the pH to 7 with saturated ammonia water, add 5-10mL of hydrazine hydrate, and place the reaction system in a 70℃ water bath, react for 3h, after the reaction is completed, transfer the mixture to a centrifuge tube and centrifuge, wash the lower liquid with deionized water 4 times, then transfer to a 50℃ vacuum drying oven and dry to constant weight, obtain modified graphene.

[0060] S2, preparation of modified tetrafluoroethylene

[0061] Weighing: 10g of modified graphene, 30g of molybdenum disulfide and 400mL of anhydrous ethanol are mixed and added to a ball mill for 10h of ball milling dispersion, after ball milling, the ball milling slurry is transferred to a beaker, 0.1g of polyethylene glycol is added, and stirred for 35min to obtain a mixed slurry;

[0062] Weighing: 40g of polytetrafluoroethylene and 2g of low molecular weight polytetrafluoroethylene are added to a ball mill and ball milled for 3h, the ball milled polytetrafluoroethylene is added to a 400mL sodium-naphthalene complex solution under nitrogen protection, the temperature is raised to 40℃, and after 25min of reaction, it is washed with deionized water until it is neutral, then 200mL of KH560 ethanol solution is added, ultrasonic for 7min, centrifugal, and put into a 60℃ vacuum drying oven to dry to constant weight, obtain pretreated polytetrafluoroethylene;

[0063] Weighing: 40g of pretreated polytetrafluoroethylene is added to a mixer, stirred at low speed for 2min, then the mixed slurry is added, stirred for 15min, then the mixture is transferred to a 70℃ vacuum drying oven and dried to constant weight, obtain modified polytetrafluoroethylene.

[0064] S3, preparation of sheath layer premix

[0065] The ultraviolet absorber UV-326, the antioxidant 1010, the dioctyl adipate and the calcium stearate are mixed according to the weight ratio of 1:0.8:4:0.8 to obtain an auxiliary additive, which is ready for use;

[0066] Weighing: 65 parts of high-pressure low-density polyethylene, 35 parts of modified polytetrafluoroethylene, 15 parts of random copolymerized polypropylene and auxiliary additive are placed in a mixer to mix, obtain a sheath layer premix.

[0067] Example 3

[0068] The present embodiment provides a preparation method of a sheath layer premix for a high transmission rate optical cable with low attenuation characteristics, comprising the following steps:

[0069] S1, preparation of modified graphene

[0070] Weighing: 10 g of flake graphite, 50 mL of concentrated sulfuric acid and 4 g of potassium permanganate were added into a beaker and mixed uniformly, the beaker was transferred to a constant temperature water bath, the temperature was raised to 40°C, and stirring was carried out for 2 h, then the temperature was raised to 60°C, and stirring was continued for 3 h, after the reaction was completed, the system was cooled to room temperature, 100 mL of deionized water was added, and filtration was carried out, the filter cake was washed with deionized water until it was neutral, and then it was transferred to a 80°C vacuum drying oven for drying until the weight was constant, the dried graphite powder was ground and placed in a muffle furnace, heated to 1000°C at a heating rate of 10°C / s, and kept for 2 min, and expanded graphite was obtained;

[0071] Weighing: 50 mL of concentrated sulfuric acid and 1 g of sodium nitrate were mixed uniformly in a beaker, 5 g of expanded graphite was added, stirred for 20 min, the temperature was controlled at 30°C, 7.5 g of potassium permanganate was added, and the reaction was carried out for 2 h, 100 mL of deionized water was added, the temperature was raised to 50°C, and 30 wt% hydrogen peroxide solution was added until the solution color changed from brownish to bright yellow, after the reaction was completed, the system was cooled to room temperature, filtration was carried out, the filter cake was washed with deionized water until it was neutral, and then it was transferred to a 60-80°C vacuum drying oven for drying until the weight was constant, and oxidized graphite was obtained;

[0072] Weighing: 5 g of oxidized graphite, 1000 mL of deionized water were added into a beaker, ultrasonic treatment was carried out at room temperature for 2 h, saturated ammonia water was used to adjust the pH to 7, 10 mL of hydrazine hydrate was added, the reaction system was placed in a 80°C water bath, and the reaction was carried out for 4 h, after the reaction was completed, the mixture was transferred to a centrifuge tube, the lower liquid was washed with deionized water for 5 times, and then it was transferred to a 60°C vacuum drying oven for drying until the weight was constant, and modified graphene was obtained.

[0073] S2, preparation of modified polytetrafluoroethylene

[0074] Weighing: 10 g of modified graphene, 30 g of molybdenum disulfide and 400 mL of anhydrous ethanol were mixed and added into a ball mill for ball milling dispersion for 12 h, after the ball milling was completed, the ball milling slurry was transferred to a beaker, 0.1 g of polyethylene glycol was added, and stirring was carried out for 40 min, and a mixed slurry was obtained;

[0075] Weighing: 40 g of polytetrafluoroethylene and 2 g of low molecular weight polytetrafluoroethylene were added into a ball mill for ball milling for 4 h, the ball-milled polytetrafluoroethylene was added into a 400 mL sodium-naphthalene complex solution under nitrogen protection, the temperature was raised to 45°C, and the reaction was carried out for 30 min, then deionized water was used for washing until it was neutral, and then 200 mL of KH560 ethanol solution was added, ultrasonic treatment was carried out for 80 min, centrifugation was carried out, and the product was placed in a 60°C vacuum drying oven for drying until the weight was constant, and pretreated polytetrafluoroethylene was obtained;

[0076] Weighing: 40 g of pretreated polytetrafluoroethylene was added into a mixer, low-speed stirring was carried out for 2 min, the mixed slurry was added, stirring was carried out for 20 min, and then the mixture was transferred to a 80°C vacuum drying oven for drying until the weight was constant, and modified polytetrafluoroethylene was obtained.

[0077] S3, preparing a sheath layer premix

[0078] The ultraviolet absorber UV-326, the antioxidant 1010, the dioctyl adipate and the calcium stearate are mixed in a weight ratio of 1:0.8:4:0.8 to obtain an auxiliary additive, which is ready for use.

[0079] 70 parts of high-pressure low-density polyethylene, 40 parts of modified polytetrafluoroethylene, 20 parts of random copolymerized polypropylene and the auxiliary additive are weighed in parts by weight and mixed in a mixer to obtain a sheath layer premix.

[0080] Example 4

[0081] The embodiment provides a preparation method of a high-transmission-rate optical cable with low attenuation characteristics, and the method comprises the following steps:

[0082] Step one, wrapping

[0083] A plurality of optical fibers are arranged in parallel, a loose tube is wrapped around the periphery of the optical fibers, an oil paste is filled in the gap between the optical fibers and the loose tube, and a wrapping tape is wrapped outside the loose tube to form an insulation layer.

[0084] Step two, extrusion molding

[0085] The sheath layer premix prepared in Example 1 is added to a double-screw extruder, the temperatures of six temperature zones of the double-screw extruder from the feeding end to the discharging end are 80 DEG C, 150 DEG C, 220 DEG C, 280 DEG C, 250 DEG C and 280 DEG C in sequence, the main shaft rotating speed of the double-screw extruder is adjusted, and the molten mixing is maintained for 10 min, the sheath layer is extruded and coated outside the insulation layer, and after cooling and molding, a high-transmission-rate optical cable is prepared.

[0086] Example 5

[0087] The embodiment provides a preparation method of a high-transmission-rate optical cable with low attenuation characteristics, and the method comprises the following steps:

[0088] Step one, wrapping

[0089] A plurality of optical fibers are arranged in parallel, a loose tube is wrapped around the periphery of the optical fibers, an oil paste is filled in the gap between the optical fibers and the loose tube, and a wrapping tape is wrapped outside the loose tube to form an insulation layer.

[0090] Step two, extrusion molding

[0091] The sheath layer premix prepared in Example 2 is added to a twin-screw extruder, and the temperature of each of the six temperature zones of the twin-screw extruder from the feeding end to the discharging end is 100℃, 175℃, 260℃, 300℃, 275℃, 300℃, respectively. The main shaft rotation speed of the twin-screw extruder is adjusted, and the melt mixing is maintained for 13 min. The sheath layer is extruded and coated outside the insulation layer. After cooling and molding, a high transmission rate optical cable is prepared.

[0092] Example 6

[0093] The present embodiment provides a preparation method of a high transmission rate optical cable with low attenuation characteristics, comprising the following steps:

[0094] Step one, wrapping

[0095] A plurality of optical fibers are arranged in parallel. A loose tube is wrapped around the periphery of the optical fibers. An oil paste is filled in the gap between the optical fibers and the loose tube. A wrapping tape is wrapped outside the loose tube to form an insulation layer.

[0096] Step two, extrusion molding

[0097] The cable material prepared in Example 3 is added to a twin-screw extruder, and the temperature of each of the six temperature zones of the twin-screw extruder from the feeding end to the discharging end is 120℃, 200℃, 280℃, 320℃, 300℃, 320℃, respectively. The main shaft rotation speed of the twin-screw extruder is adjusted, and the melt mixing is maintained for 15 min. The sheath layer is extruded and coated outside the insulation layer. After cooling and molding, a high transmission rate optical cable is prepared.

[0098] Comparative Example 1

[0099] The difference between the present comparative example and Example 6 is that the sheath layer premix prepared in Example 3 is used, and in step S2, modified polytetrafluoroethylene is prepared without adding modified graphene.

[0100] Comparative Example 2

[0101] The difference between the present comparative example and Example 6 is that the sheath layer premix prepared in Example 3 is used, and in step S2, modified polytetrafluoroethylene is prepared without adding molybdenum disulfide.

[0102] Comparative Example 3

[0103] The difference between the present comparative example and Example 6 is that the sheath layer premix prepared in Example 3 is used, and in step S3, polytetrafluoroethylene prepared in step S2 is used instead of modified polytetrafluoroethylene.

[0104] Comparative Example 4

[0105] The difference between the present comparative example and Example 6 is that the sheath layer premix prepared in Example 3 is used, and step S2 is cancelled, and no modified polytetrafluoroethylene is added in the cable material.

[0106] Performance test:

[0107] The tensile strength and elongation at break of the cable samples prepared in Examples 4-6 and Comparative Examples 1-4 were determined according to the standard XF 306.1-2007 "Flame-retardant and fire-resistant cable plastic insulation Flame-retardant and fire-resistant cable classification and requirements Part 1: Flame-retardant cable".

[0108] The attenuation properties of the cable samples prepared in Examples 4-6 and Comparative Examples 1-4 were determined according to the standard GB / T 17737.113-2024 "Coaxial communication cable Part 1-113: Electrical test methods Attenuation constant test".

[0109] The environmental adaptability of the cable samples prepared in Examples 4-6 and Comparative Examples 1-4 was determined according to the standard GB / Z 41287.1-2022 "Building entry optical cable for communication Part 1: Pipeline and direct-buried entry optical cable", and the specific test results are shown in Table 1.

[0110] Table 1 - Performance test data table of the samples

[0111] Group item Tensile strength / MPa Elongation at break / % Attenuation constant / dB·km -1 ]] Temperature attenuation / grade Example 4 16.8 208.6 0.15 Grade 1 Example 5 17.2 209.7 0.14 Grade 1 Example 6 16.9 207.8 0.16 Grade 1 Comparative Example 1 14.3 168.5 0.17 Grade 2 Comparative Example 2 14.6 169.5 0.18 Grade 2 Comparative Example 3 14.1 164.3 0.20 Grade 2 Comparative Example 4 13.8 163.2 0.21 Grade 2

[0112] Data analysis:

[0113] Comparative analysis of the data in the above table shows that the tensile strength of the sheath layer of the cable prepared by the present application reaches 17.2 MPa, the elongation at break reaches 209.7%, and the attenuation constant reaches 0.14 dB·km -1 , and the temperature attenuation grade is 1, and all performance parameters are better than the comparative examples, which shows that the present application fills polytetrafluoroethylene with modified graphene and molybdenum disulfide, which not only effectively improves the mechanical properties and environmental adaptability of the optical cable, but also effectively improves the transmission rate of the optical cable.

[0114] Comparative Example 1 and the example, the two-dimensional sp2 hybrid carbon atoms of graphene form a highly conjugated pi electron system, when uniformly dispersed in the polytetrafluoroethylene matrix, the pi electron cloud of graphene can weaken the dipole orientation polarization of the polytetrafluoroethylene molecular chain through the electronic shielding effect, reduce the dielectric constant and dielectric loss, thereby reducing signal attenuation and improving transmission rate, and at the same time, affected by the lamellar structure of the modified graphene, the mechanical properties of the cable are improved;

[0115] Compared with the example, the d-orbital electrons of molybdenum disulfide are delocalized in the layer, but the interlayer electron transfer is limited, forming a dielectric barrier. When dispersed in polytetrafluoroethylene, the layered structure can be aligned in the direction of the electric field, forming a similar dielectric nanolayer, hindering charge migration, reducing leakage current, and reducing the orientation polarization of polar CF2 groups in the interlayer gap, further reducing dielectric loss and improving the transmission rate of the optical cable.

[0116] Compared with the example, the modified polytetrafluoroethylene combines with fillers such as graphene and molybdenum disulfide to reduce local overheating at high transmission rates with the assistance of graphene and molybdenum disulfide, further reducing friction and improving the flexibility of the optical cable during laying. In cooperation with the matrix resin, a multi-layer insulation protection is formed to strengthen the stability of signal transmission.

[0117] Compared with the example, polytetrafluoroethylene has high heat resistance and weather resistance, which can resist the heat accumulation of the optical cable due to current or signal loss at high transmission rates, avoid cable material softening, deformation or aging due to high temperature, ensure the stable operation of the optical cable in high temperature environment, and reduce the structural damage caused by temperature fluctuations.

[0118] The preferred embodiments of the above disclosed application are only used to help explain the application. The preferred embodiments do not describe all the details and limit the application to specific embodiments. Obviously, many modifications and changes can be made according to the content of the specification. The specification selects and describes these embodiments in order to better explain the principles and practical applications of the application, so that those skilled in the art can well understand and utilize the application. The application is limited by the claims and their entire scope and equivalents.

Claims

1. A high transmission rate optical cable of low attenuation characteristics, characterized by, The high transmission rate optical cable comprises optical fibers, loose tubes, insulation layers and sheath layers arranged in sequence from inside to outside, gaps are left between the optical fibers and the loose tubes, and the gaps are filled with ointment; The sheath layer comprises, by weight fraction, 60-70 parts of high-pressure low-density polyethylene, 30-40 parts of modified polytetrafluoroethylene, 10-20 parts of random copolymerized polypropylene and 3-5 parts of auxiliary additives, wherein the auxiliary additives are composed of ultraviolet absorber UV-326, antioxidant 1010, dioctyl adipate and calcium stearate in a weight ratio of 1:0.8:4:0.8; The preparation method of the modified polytetrafluoroethylene comprises the following steps: A1, the modified graphene, molybdenum disulfide and anhydrous ethanol are mixed and added into a ball mill for ball milling dispersion for 8-12 hours, after the ball milling is completed, the ball milling slurry is transferred to a beaker, polyethylene glycol is added and stirred for 30-40 minutes to obtain a mixed slurry; A2, the pretreated polytetrafluoroethylene is added into a mixer and stirred at a low speed for 1-2 minutes, then the mixed slurry is added and stirred for 10-20 minutes, and then the mixture is transferred to a vacuum drying box at 60-80°C for drying to constant weight to obtain the modified polytetrafluoroethylene.

2. A high transmission rate optical cable with low attenuation characteristics according to claim 1, characterized in that, The optical fibers are made of quartz glass with a purity of 99.99%, the loose tubes are made of polypropylene material or nylon material, and the insulation layer is made of poly-p-phenyleneterephthalamide.

3. A high transmission rate cable with low attenuation characteristics according to claim 1, wherein, In step A1, the amount ratio of the modified graphene, molybdenum disulfide, anhydrous ethanol and polyethylene glycol is 1g:3g:40mL:0.01-0.02g, and the type of polyethylene glycol is PEG-400.

4. A high transmission rate cable with low attenuation characteristics according to claim 3, wherein, In step A2, the weight ratio of the pretreated polytetrafluoroethylene and the mixed slurry is 4:

1.

5. A high transmission rate cable with low attenuation characteristics according to claim 4, characterized in that, The pretreatment method of the pretreated polytetrafluoroethylene is as follows: the polytetrafluoroethylene and low-molecular-weight polytetrafluoroethylene are added into a ball mill for ball milling for 2-4 hours, the ball-milled polytetrafluoroethylene is added into a sodium-naphthalene complex solution under nitrogen protection, the temperature is raised to 35-45°C, and after reaction for 20-30 minutes, the polytetrafluoroethylene is washed to neutral with deionized water, then a KH560 ethanol solution is added, ultrasonic treatment is performed for 60-80 minutes, and centrifugal drying is performed to obtain the pretreated polytetrafluoroethylene.

6. A high transmission rate cable with low attenuation characteristics according to claim 5, wherein, The amount ratio of the polytetrafluoroethylene, low-molecular-weight polytetrafluoroethylene, sodium-naphthalene complex solution and KH560 ethanol solution is 20g:1g:200mL:100mL; the sodium-naphthalene complex solution is composed of naphthalene, sodium and tetrahydrofuran in an amount ratio of 0.2g:0.5g:50mL; and the KH560 ethanol solution is composed of γ-glycidyl ether propyltrimethoxysilane, ethanol and water in a volume ratio of 1:8:

1.

7. A high transmission rate cable with low attenuation characteristics according to claim 1, wherein, In step A1, the preparation method of the modified graphene is as follows: B1, flake graphite, concentrated sulfuric acid and potassium permanganate are added into a beaker and uniformly mixed, the beaker is transferred into a constant-temperature water bath, the temperature is raised to 30-40°C, and stirring reaction is performed for 1-2 hours, then the temperature is raised to 50-60°C, and stirring reaction is continuously performed for 2-3 hours, after the reaction is completed, the product is filtered, washed and dried, and is heated to expand to obtain expanded graphite; B2, after mixing concentrated sulfuric acid and sodium nitrate uniformly in a beaker, adding expanded graphite, stirring for 15-20 min, controlling the temperature at 20-30 DEG C, adding potassium permanganate, reacting for 1-2 h, adding deionized water, heating to 40-50 DEG C, adding 30 wt% hydrogen peroxide solution until the solution color changes from brown to bright yellow, filtering, washing and drying to obtain oxidized graphite; B3, adding oxidized graphite and deionized water into a beaker, ultrasonicating at room temperature for 1-2 h, adjusting pH to 6.5-7.5 with saturated ammonia water, adding hydrazine hydrate, placing the reaction system in a 60-80 DEG C water bath, reacting for 2-4 h, and post-treating to obtain modified graphene.

8. A high transmission velocity cable with low attenuation characteristics according to claim 7, characterized in that, In step B1, the amount ratio of the flake graphite, concentrated sulfuric acid and potassium permanganate is 2 g:10 mL:1 g; The heating expansion step is: after grinding the dried graphite powder, heating to 800-1000 DEG C at a heating rate of 5-10 DEG C / s in a muffle furnace, and keeping the temperature for 1-2 min to obtain expanded graphite; in step B2, the amount ratio of the concentrated sulfuric acid, sodium nitrate, expanded graphite, potassium permanganate and deionized water is 50 mL:1 g:5 g:7.5 g:100 mL; in step B3, the amount ratio of the oxidized graphite, deionized water and hydrazine hydrate is 1 g:200 mL:1-2 mL; the post-treatment step includes: after the reaction is completed, transferring the mixture to a centrifuge tube, centrifuging, washing the lower liquid with deionized water for 3-5 times, and then transferring to a 40-60 DEG C vacuum drying oven to dry to constant weight to obtain modified graphene.

9. A method of making a high bandwidth optical fiber cable as claimed in any one of claims 1-8, characterized in that, Comprising the following steps: S1, placing high-pressure low-density polyethylene, modified polytetrafluoroethylene and random copolymerized polypropylene in a mixing mill, increasing the temperature to 280-320 DEG C, adding auxiliary additives and mixing uniformly to obtain a premix; S2, placing the premix in a double-screw extruder to melt and extrude outside the insulation layer, and cooling and shaping to obtain a sheath layer, thereby preparing a high-transmission-rate optical cable.

10. The method of claim 9, wherein the low attenuation high transmission rate optical cable is prepared by the steps of: In step S1, the temperatures of the six temperature zones of the double-screw extruder from the feeding end to the discharging end are 80-120 DEG C, 150-200 DEG C, 220-280 DEG C, 280-320 DEG C, 250-300 DEG C and 280-320 DEG C, respectively.