A heat-insulating optical cable, a photocuring resin and a manufacturing method of the optical cable

Abstract

The present invention discloses a heat-insulating optical cable, a photocurable resin and a manufacturing method of the optical cable. The optical unit sheath and / or the outer sheath of the optical cable is a sheath with a heat-insulating film; the sheath with a heat-insulating film includes a tightly combined sheath material layer and a crystalline polymer porous film layer; the crystalline polymer porous film has a porosity of 30% - 50%, a crystallinity of 20 - 40%, and a thickness between 5 - 25 μm; the sheath material layer has a thickness between 0.15 - 3 mm; the peel force between the sheath material layer and the crystalline polymer porous film layer is between 10 N - 50 N. The photocurable resin precursor solution contains a film-forming agent with a mass fraction of 8 - 12%, and the balance is a photocurable resin precursor matrix solution, which is applied to form the crystalline polymer porous film layer. The heat-insulating optical cable provided by the present invention reduces the influence of extreme temperatures on the sheath material layer.

Description

Technical Field

[0001] The present invention belongs to the field of optical communication, and more specifically, relates to a heat-insulating optical cable, a photocurable resin, and a method for manufacturing an optical cable. Background Art

[0002] With the rapid development of optical fiber communication, its application environment has become complex and changeable, thus posing higher requirements for the temperature resistance of the protective layer of the optical fiber, i.e., the optical cable. Such as temperature measurement in underground pipe galleries, oil well exploration, airborne communication, etc.

[0003] Especially in the nuclear power application environment, due to the physical characteristics of radiation-resistant optical fiber cables such as thin diameter, small volume, light weight, and radiation resistance, in terms of signal transmission, the optical fiber has low transmission loss and large bandwidth. At the same time, since most optical fibers and optical waveguide devices are dielectric materials and have no electromagnetic radiation, after changing the cable-based transmission system to optical fiber transmission, not only can the transmission speed and transmission capacity be greatly improved, but it is especially suitable for applications inside the containment of nuclear power plants. Due to the particularity of its application, nuclear power plants require their cables to use low-smoke, halogen-free, flame-retardant materials as sheath materials. However, when the nuclear power optical cable is applied inside the containment, it needs to meet the design requirements for abnormal working conditions, with a temperature as high as 121 °C for at least 72 hours, and the abnormal working conditions need to be carried out 5 times, and normal communication should be restored after the abnormal working conditions end. Currently, for nuclear power optical cables with a conventional low-smoke, halogen-free, flame-retardant sheath, the optical fiber tight jacket, sub-units, and sheath will adhere to each other at 121 °C, increasing the optical fiber signal transmission loss and even blocking the signal.

[0004] Currently, in order to improve the heat insulation performance of the optical cable, it is necessary to increase fillers such as sponges or increase the heat insulation coating layer, resulting in a significant increase in the diameter of the optical cable. Chinese patent document CN216248449U provides an optical cable applied to an environmental temperature of 120 °C, using a polyester film or a polyimide film as the heat insulation layer to protect the optical fiber in the loose tube. However, due to the poor combination of the heat insulation layer and the sheath, the heat insulation effect is limited. More importantly, the outer sheath itself has poor heat insulation and heat resistance performance and is easily damaged in an extreme temperature environment, and the damage of the outer sheath will exacerbate the impact of extreme temperature on the performance of the optical cable. Summary of the Invention

[0005] In view of the above deficiencies or improvement requirements of the prior art, the present invention provides a heat-insulating optical cable, a photocurable resin, and a method for manufacturing an optical cable. The purpose is to form a crystalline polymer porous film layer with closed micropores on the sheath structures of each sub-structure of the optical cable, which is closely combined with the sheath structure, so as to manufacture a heat-insulating optical cable with a wider application range and better heat-insulating effect without significantly increasing the diameter of the optical cable. In particular, the closely combined sheath and the porous film layer are not easily damaged in an extreme temperature environment, so it is applicable not only to loose tube or tight buffer fiber sheaths, but also to the outer sheath structure of the optical cable, thus solving the technical problems of the prior art that the diameter of the heat-insulating optical cable is large, the heat-insulating effect is poor, and it cannot be applied to extreme environments.

[0006] To achieve the above object, according to one aspect of the present invention, there is provided a heat-insulating optical cable, wherein the optical unit sheath and / or the outer sheath of the optical cable is a sheath with a heat-insulating film;

[0007] The sheath with a heat-insulating film includes a closely combined sheath material layer and a crystalline polymer porous film layer;

[0008] The crystalline polymer porous film has a porosity of 30%-50%, preferably 30%-42%; a crystallinity of 20-40%, preferably 25-30%; a thickness between 5-25 μm, preferably 10-20 μm; and preferably an average pore diameter between 2-4 μm;

[0009] The sheath material layer has a thickness of 0.15-3 mm;

[0010] The peel force between the sheath material layer and the crystalline polymer porous film layer is between 10 N and 50 N.

[0011] Preferably, for the heat-insulating optical cable, the bending modulus of the crystalline polymer porous film is between 5 MPa and 20 MPa, preferably between 8 MPa and 15 MPa, and its coefficient of thermal expansion matches that of the sheath material layer.

[0012] Preferably, for the heat-insulating optical cable, the crystalline polymer is a photocurable resin, preferably a high-temperature resistant resin, such as polyphenylene sulfide resin, polyether ether ketone, polyether ketone, and polyimide.

[0013] Preferably, for the heat-insulating optical cable, the crystalline polymer contains a nucleating agent with a mass fraction between 8-12%; the nucleating agent preferably contains dip-coated chitosan, and preferably adopts a polyvinyl alcohol film-forming system.

[0014] Preferably, for the heat-insulating optical cable, the thickness ratio of the sheath material layer to the crystalline polymer porous film layer is between 20-500:1.

[0015] Preferably, for the heat-insulating optical cable, the optical unit sheath is a loose tube or an optical fiber tight coating layer.

[0016] Preferably, for the heat-insulating optical cable, the outer sheath of the optical cable is a sheath with a heat-insulating film;

[0017] The sheath material layer is made of anti-irradiation low-smoke halogen-free flame-retardant polyolefin, and the crystalline polymer porous membrane layer is formed of photocured polyphenylene sulfide resin.

[0018] According to another aspect of the present invention, a photocurable resin coating is provided, and the photocurable resin precursor solution contains a film-forming agent with a mass fraction of 8-12%, and the balance is a photocurable resin precursor matrix solution;

[0019] The film-forming agent includes, by mass:

[0020] 50 to 80 parts of a volatile solvent, 10-20 parts of a nucleating agent, and 10 to 20 parts of a precursor monomer;

[0021] The nucleating agent is dip-coated chitosan;

[0022] The precursor monomer is polyvinyl alcohol.

[0023] Preferably, for the photocurable resin coating, the volatile solvent is N-methylpyrrolidone and / or formic acid;

[0024] The mass fraction of N-methylpyrrolidone is between 40 and 60 parts;

[0025] The mass fraction of formic acid is between 10 and 20 parts.

[0026] Preferably, for the photocurable resin coating, the photocurable resin precursor matrix solution includes, by mass:

[0027] 40 to 70 parts of a monomer, 5 to 10 parts of a plasticizer, 2 to 3 parts of a lubricant, 1-10 parts of a photoinitiator, and 1-10 parts of a catalyst;

[0028] Preferably, it includes 5-20 parts of inorganic particles.

[0029] According to another aspect of the present invention, the application of the photocurable resin coating is provided, and it is applied to form a crystalline polymer porous membrane layer;

[0030] For the crystalline polymer porous membrane, the porosity is 30%-50%, preferably 30%-42%; the crystallinity is 20-40%, preferably 25-30%; the thickness is between 5 and 25 μm, preferably 10-20 μm; preferably, the average pore diameter is between 2 and 4 μm.

[0031] According to another aspect of the present invention, there is provided a method for manufacturing the heat-insulating optical cable, which combines the components of the optical cable and forms the optical unit sheath or the outer sheath of the optical cable according to the following method:

[0032] Extrusion: Extrude the sheath material to form a sheath material layer;

[0033] Coating: Maintain the temperature of the sheath material layer between 40 and 60 °C, fixedly coat the photocurable resin coating as described in any one of claims 8 to 10 on the outer side of the sheath material layer and cure its coating layer by ultraviolet light treatment to form a coating layer with a preset thickness, obtaining a sheath preform;

[0034] Pore formation: Maintain the temperature of the sheath preform at 80 - 100 °C and apply an axial tension of 2 - 50 N for a duration of 10 - 30 s, so that the coating layer of the sheath preform forms a crystalline polymer porous membrane layer with a porous structure.

[0035] Preferably, in the method for manufacturing the heat-insulating optical cable, the ultraviolet light treatment controls the ultraviolet light power between 0.10 - 1.0 J / cm 2 2.

[0036] Generally speaking, compared with the prior art through the above technical solutions conceived by the present invention, the following beneficial effects can be achieved:

[0037] For the heat-insulating optical cable provided by the present invention, the optical unit sheath and / or the outer sheath of the optical cable is a sheath with a heat-insulating film. Since a crystalline polymer porous membrane layer is tightly combined on the outer side of the sheath material layer, and the crystalline polymer porous membrane layer plays a role in heat insulation, the influence of extreme temperature on the sheath material layer is reduced, and the sheath material layer has a longer service life in an extreme temperature environment.

[0038] And importantly, this tightly combined sheath with a heat-insulating film can not only be used for the optical unit sheath of the loose tube or tight sleeve layer inside the optical cable, but also be used for the manufacture of the outer sheath of the optical cable, thereby extending the service life of the outer sheath. In a preferred embodiment, for the heat-insulating optical cable provided by the present invention, compared with the prior art where the outer sheath is a heat-insulating layer that can only be arranged inside the outer sheath of the optical cable, the heat-insulating optical cable of the present invention can avoid the loss of the service life of the outer sheath caused by extreme temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a schematic cross-sectional structure diagram of the heat-insulating optical cable provided in Embodiment 1 of the present invention;

[0040] Figure 2 is a schematic cross-sectional structure diagram of the heat-insulating optical cable provided in Embodiment 2 of the present invention.

[0041] In all the drawings, the same reference numerals are used to denote the same elements or structures, where: 1 is an optical fiber subunit, 2 is a radiation-resistant reinforcement member, 3 is a radiation-resistant flame-retardant outer sheath, 4 is an anti-radiation optical fiber, 5 is a tight jacket layer, 6 is a subunit radiation-resistant sheath, 7 is a radiation-resistant flame-retardant subunit sheath material layer, 8 is a crystalline polymer porous membrane layer of the radiation-resistant flame-retardant subunit, and 9 is a crystalline polymer porous membrane of the radiation-resistant flame-retardant outer sheath. Detailed implementation manners

[0042] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various implementation manners of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0043] The heat-insulating optical cable provided by the present invention has a sheath with a heat-insulating film for the optical unit sheath and / or the outer sheath of the optical cable; the optical unit sheath is a loose tube or an optical fiber tight jacket layer.

[0044] The sheath with a heat-insulating film includes a tightly combined sheath material layer and a crystalline polymer porous membrane layer;

[0045] The crystalline polymer porous membrane has a porosity of 30%-50%, preferably 30%-42%; a crystallinity of 20-40%, preferably 25-30%; and a thickness between 5-25 μm, preferably 10-20 μm.

[0046] Since it is necessary to achieve a heat preservation effect on the surface of the outer sheath of the optical cable or outside the optical unit without significantly affecting the cable diameter and the mechanical properties of the sheath, loose tube or tight jacket layer, it is necessary to form a heat preservation structure with good mechanical properties within an extremely thin thickness range. The present invention uses a crystalline polymer to form a film within this thickness range, and tries to form a large number of micropores on the crystalline polymer. The average pore diameter is between 2-4 μm, and the micropores are in a closed state, preventing the gas molecules in the air from flowing. Even if the thickness of the crystalline polymer porous membrane is extremely thin, it can still isolate heat conduction and exhibit excellent heat preservation performance with an extremely low thermal conductivity. In order to minimize the increase in the cable diameter, it is necessary to control the porosity to be 30-50% and the crystallinity to be 20-40% at a thickness of 5-25 μm to effectively improve the heat insulation effect of the sheath; in addition, when the porosity of the crystalline polymer porous membrane is 30%-42% and the crystallinity is 25-30%, the mechanical properties are good and do not affect the protection of the optical unit, optical fiber and other structures by the sheath of the optical cable.

[0047] Preferably, the bending modulus of the crystalline polymer porous membrane is between 5 MPa and 20 MPa, preferably between 8 MPa and 15 MPa, and its coefficient of thermal expansion matches that of the sheath layer, that is, the coefficients of thermal expansion of the two are of the same order of magnitude, that is, the difference does not exceed 10 times. The coefficient of thermal expansion of the crystalline polymer porous membrane is between 3 and 9×10 -7 / K. When the crystalline polymer porous membrane and the sheath layer have comparable coefficients of thermal expansion, the crystalline polymer layer is not likely to bulge and fall off under large changes in the external environmental temperature. Especially when the optical cable works in a high-temperature environment for a long time, the coefficient of thermal expansion is an important factor determining the service life of the optical cable. The coefficient of thermal expansion is directly related to the porosity. The bending modulus of the crystalline polymer porous membrane is an important parameter for maintaining the porosity, which is determined by the pore size and pore distribution of the porous membrane. A porous membrane with too high a bending modulus is significantly brittle and is likely to be crushed and peeled off during repeated bending or friction during use; while a porous membrane with too low a bending modulus cannot effectively maintain the closed state of the pores, resulting in poor heat insulation effect.

[0048] The crystalline polymer is preferably a photocurable resin, more preferably a high-temperature resistant resin, such as polyphenylene sulfide resin, polyether ether ketone, polyether ketone, polyimide, etc., and the temperature resistance can reach 260 °C;

[0049] The crystalline polymer contains a film-forming agent with a mass fraction of 8-12%. The film-forming agent preferably contains dip-coated chitosan, and a more preferred choice is a polyvinyl alcohol film-forming system, which has a high nucleation efficiency. The typical formula is as follows:

[0050] 10-20 parts of dip-coated chitosan, 10-20 parts of polyvinyl alcohol, and 10-20 parts of formic acid.

[0051] The sheath layer has a thickness of 0.15-3 mm, and its maximum temperature resistance level is 85 °C; the material of the sheath layer is specifically selected according to whether the sheath is specifically used as an optical unit sheath or an optical cable outer sheath. In the preferred scheme, when a photocurable resin is used to form the crystalline polymer porous membrane, for the vast majority of existing sheath material types, a relatively tight combination can be formed to meet the peel strength requirements between the sheath layer and the crystalline polymer porous membrane layer.

[0052] Especially, when applied to the outer sheath of an optical cable in a high-temperature irradiation environment, such as the outer sheath of a nuclear power communication optical cable, the sheath layer adopts an anti-irradiation low-smoke halogen-free flame-retardant polyolefin, combined with a crystalline polymer porous membrane layer formed by a high-temperature resistant photocurable polyphenylene sulfide resin, so that the optical cable can not only withstand high temperatures up to 121 °C for 607 h, but also has a high radiation resistance dose, and the service life of the nuclear power communication optical cable can reach 60 years.

[0053] The peeling force between the sheath material layer and the crystalline polymer porous membrane layer is between 10 N and 50 N, and the peeling force is tested by the annular peeling method; the thickness ratio between the sheath material layer and the crystalline polymer porous membrane layer is between 20 and 500:1.

[0054] When both the optical unit sheath and the outer sheath adopt the sheath structure with a heat insulation film provided by the present invention, according to the tray principle, heat conduction can be effectively isolated, and the influence of extreme high temperature on the optical fiber can be greatly weakened.

[0055] The crystalline polymer porous membrane layer forming the sheath with a heat insulation film is preferably made of a photocurable resin coating.

[0056] The precursor solution of the photocurable resin coating contains a film-forming agent with a mass fraction of 8-12%, and the balance is the precursor matrix solution of the photocurable resin;

[0057] The film-forming agent includes, by mass:

[0058] 50 to 80 parts of a volatile solvent, 10-20 parts of a nucleating agent, and 10 to 20 parts of a precursor monomer; the nucleating agent is dip-coated chitosan; the precursor monomer is polyvinyl alcohol; the volatile solvent is N-methylpyrrolidone or formic acid; the mass fraction of N-methylpyrrolidone is between 40-60 parts; the mass fraction of formic acid is between 10-20 parts.

[0059] The preferred formulation of the film-forming agent is:

[0060] 40-60 parts of N-methylpyrrolidone, 10-20 parts of dip-coated chitosan, 10-20 parts of polyvinyl alcohol, and 10-20 parts of formic acid. During the film-forming process, the nucleating agent dip-coated chitosan and the precursor monomer polyvinyl alcohol have good wettability and quickly crosslink to form a film, helping to form a stable semi-crystalline film.

[0061] Applied in a high-temperature environment, the precursor matrix solution of the photocurable resin is preferably a high-temperature-resistant precursor matrix solution of the photocurable resin, such as polyphenylene sulfide resin, polyether ether ketone, polyether ketone, and polyimide precursor matrix solution, and further includes the following components by mass fraction:

[0062] 40-70 parts of a monomer, 5-10 parts of a plasticizer, 2-3 parts of a lubricant, 5-20 parts of inorganic particles, 1-10 parts of a photoinitiator, and 1-10 parts of a catalyst; among them, the inorganic particles are an optional additive component.

[0063] Among them, the plasticizer is preferably one or a combination of phthalates, alkyl phenyl sulfonates, aliphatic triacid esters, epoxy esters, phosphates, polymeric types, etc., which plays a role in adjusting the plasticity of the crystalline polymer porous membrane and ensures complete bonding with the sheath after film formation; the lubricant is preferably one or a combination of polytetrafluoroethylene and graphite, which is used to optimize the processing performance and enhance the fluidity during processing; the photoinitiator is preferably one or a combination of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, acetophenone, dimethoxy-phenylacetophenone, methyl benzoylformate, etc.; the catalyst is preferably one or a combination of hexafluoroiodoantimonic acid and dodecylbenzene; the inorganic particles are preferably nano-silicates, preferably nano-silica, which are used to improve the microporous morphology, help maintain the microporous closed state, and adjust the flexural modulus of the crystalline polymer porous membrane within a suitable range.

[0064] The manufacturing method of the heat-insulating optical cable provided by the present invention combines the components of the optical cable according to the general method and forms the optical unit sheath or the outer sheath of the optical cable according to the following method:

[0065] Extrusion: Extrude the sheath material to form a sheath material layer;

[0066] Coating: Maintain the temperature of the sheath material layer between 40 - 60 °C to increase the peel strength between the sheath layer and the heat-insulating film; fixedly coat the photocurable resin coating provided by the present invention on the outside of the sheath material layer and cure its coating layer by ultraviolet light treatment to form a coating layer with a preset thickness, and obtain a sheath preform. Among them, the fixed coating is preferably: passing through the inlet die and the outlet die of the coater, coating the precursor solution of the photocurable resin on its surface, and controlling the thickness of the heat-insulating film by controlling the size difference between the inlet die and the outlet die to form a coating layer with a preset thickness. The ultraviolet light treatment controls the power of the ultraviolet lamp between 0.10 - 1.0 J / cm 2 between;

[0067] Pore formation: Maintain the temperature of the sheath preform at 80 - 100 °C and apply an axial tension of 2 - 50 N for a duration of 10 - 30 s, so that the coating layer of the sheath preform forms a crystalline polymer porous membrane layer with a porous structure.

[0068] For the gradually curing crystalline polymer, under the synergistic action of heating and tensile force, the solvent rapidly volatilizes, forming a pore structure while controlling the crystallinity of the crystalline polymer to form a stable semi-crystalline porous membrane.

[0069] The crystalline polymer layer forms semi-crystals during the curing process and forms a porous structure under tension. The intensity of ultraviolet light and the content of photoinitiator affect the curing rate of the crystalline polymer layer. The temperature, tension magnitude, and application time of the film-forming process determine the solvent evaporation rate. By controlling the intensity of ultraviolet light, the content of photoinitiator, and the temperature, tension magnitude, and application time of the pore-forming process, and coordinating with the precise content of film-forming agent, the semi-crystalline porous membrane is made to form stable micropores of a preset specification.

[0070] The following are examples:

[0071] In the examples: The plasticizer is diethyl phthalate; the lubricant is polytetrafluoroethylene; the inorganic particles are nano-silica; the photoinitiator is 2,4-diethylthioxanthone; the catalyst is titanium dioxide.

[0072] Example 1

[0073] The heat-insulating optical cable provided in this example, as Figure 1 shown, includes an optical fiber sub-unit 1, a radiation-resistant strengthening member 2, and a radiation-resistant flame-retardant outer sheath 3.

[0074] An anti-radiation optical fiber 4, a tight buffer layer 5, and a sub-unit radiation-resistant sheath 6 are arranged inside the optical fiber sub-unit 1; after the sub-units 1 are stranded, they are wrapped around the radiation-resistant strengthening member 2, and a radiation-resistant flame-retardant outer sheath 3 is extruded and coated outside the radiation-resistant strengthening member. The outer diameter of the tight buffer layer is 500um, the radiation-resistant flame-retardant outer sheath 3 and the radiation-resistant flame-retardant sub-unit sheath are both radiation-resistant low-smoke and halogen-free materials, the outer diameter of the optical fiber sub-unit is 1.2 - 1.5mm, and the thickness of the radiation-resistant flame-retardant outer sheath 3 is 0.15 - 3mm.

[0075] Among them, the sub-unit radiation-resistant sheath is a sheath with a heat-insulating film, including:

[0076] A radiation-resistant flame-retardant sub-unit sheath layer 7, a crystalline polymer porous membrane layer 8;

[0077] The thickness of the radiation-resistant flame-retardant sub-unit sheath 7 is 0.15mm; the coefficient of thermal expansion is 9*10 -7 / k;

[0078] The crystalline polymer porous membrane layer 8 has a porosity of 30 - 42%, a crystallinity of 25 - 30%, and a thickness of 10 - 15um; the flexural modulus is between 5MPa and 20MPa, and the coefficient of thermal expansion is 3 - 9*10 -7 / k.

[0079] The photocurable resin coating used in this example has the following composition as shown in Table 1-1:

[0080] Table 1-1 Composition Table of Photocurable Resin Coating

[0081]

[0082]

[0083] The manufacturing method of the thermal insulation optical cable of this embodiment is as follows:

[0084] A radiation-resistant single-mode optical fiber with a diameter of 250um is placed on the pay-off rack with a pay-off tension of 0.8N. After being coated with a layer of high-temperature resistant polyacrylic resin tight jacket by a coating machine, the outer diameter is 500um, and then the fiber is cooled and blown dry before being reeled in.

[0085] Extrusion: Place 1 tight-buffered optical fiber and 4 930dtex aramid fibers on the pay-off stand, with a pay-off tension of 1.5N, and only the guide wheel and the wire collection die enter the extruder extrusion subunit sheath. The extruder is sequentially arranged from the feed port to the die mouth as follows: feed port, barrel zone 1, barrel zone 2, barrel zone 3, barrel zone 4, barrel zone 5, machine neck and die mouth, and the temperature of each zone is set as follows: feed port is 130±5℃, barrel zone 1 is 135±10℃, barrel zone 2 is 140±10℃, barrel zone 3 is 145±10℃, barrel zone 4 is 150±10℃, barrel zone 5 is 155±10℃, machine neck and die mouth are 160±10℃; the cooling area arranged at the die mouth outlet adopts segmented cooling, the first cooling section connected to the die mouth adopts a warm water cooling tank with a cooling temperature of 50±10℃, and the remaining sections are cooled by normal temperature water.

[0086] Coating: The sub-unit pay-off tension is below 5N, and the temperature is controlled between 40-60℃ after being heated in an oven. After entering the entrance die, it is light-cured and coated with a layer of light-curing coating with a thickness of 10um, and then the wire is collected after passing through the exit die.

[0087] Hole forming: The sub-unit after winding is passed through a heat preservation furnace, and an axial tension of 3N is applied through a screening guide wheel for stretching. The temperature of the heat preservation furnace is 80°C, and the cured high-temperature resistant membrane is subjected to a hole forming treatment for 10s.

[0088] Two 1.8 mm optical fiber subunits and two 1.8 mm filling ropes are drawn into a stranding machine through guide wheels and a wire collecting die for stranding, with a stranding pitch of 500 mm. Finally, a radiation-resistant and flame-retardant sheath with a thickness of 3.0 mm is extruded by a sheath extruder. The extruder is sequentially arranged in zones from the feed inlet to the die orifice as follows: feed inlet, barrel zone 1, barrel zone 2, barrel zone 3, barrel zone 4, barrel zone 5, machine neck, and die orifice. The temperatures of each zone are set as follows: the feed inlet is 130 ± 5 °C, barrel zone 1 is 135 ± 10 °C, barrel zone 2 is 140 ± 10 °C, barrel zone 3 is 145 ± 10 °C, barrel zone 4 is 150 ± 10 °C, barrel zone 5 is 155 ± 10 °C, the machine neck and die orifice are 160 ± 10 °C; the cooling area at the die orifice outlet adopts segmented cooling. The first section of cooling connected to the die orifice uses a warm water cooling tank with a cooling temperature of 50 ± 10 °C, and the remaining sections are cooled with normal temperature water.

[0089] For the heat-insulating optical cable manufactured in this embodiment, the structure and performance test results of the crystalline polymer porous membrane layer 8 are shown in Table 1-2 below:

[0090] Table 1-2

[0091]

[0092]

[0093] For the heat-insulating optical cable manufactured in this embodiment, the heat-insulating effect test method is as follows: measure the deformation time of the tight-buffered optical fiber at 125 °C. The results show that: no deformation occurred in Examples 1-1 to 1-3, while deformation occurred in Comparative Example 1-1 after 12 hours, and immediate deformation occurred in Comparative Example 1-2. This shows that for the heat-insulating optical cable prepared in this embodiment, the heat-insulating effect of the crystalline polymer porous membrane is obvious, and the high-temperature resistance performance of the optical cable is significantly improved under its action.

[0094] Example 2

[0095] The heat-insulating optical cable provided in this embodiment, as Figure 2 shown, includes an optical fiber subunit 1, a radiation-resistant strengthening member 2, and a radiation-resistant and flame-retardant outer sheath 3.

[0096] An anti-radiation optical fiber 4, a tight-buffered layer 5, a radiation-resistant strengthening member 6, and a subunit radiation-resistant sheath 7 are arranged inside the optical fiber subunit 1; after the subunit 1 is stranded, it is wrapped with a radiation-resistant strengthening member 2, and a radiation-resistant and flame-retardant outer sheath 3 is extruded and coated outside the radiation-resistant strengthening member. The outer diameter of the tight-buffered layer is 500 um. Both the radiation-resistant and flame-retardant outer sheath 3 and the radiation-resistant and flame-retardant subunit sheath 7 are radiation-resistant low-smoke and halogen-free materials. The outer diameter of the optical fiber subunit is 1.2 - 1.5 mm, and the thickness of the radiation-resistant and flame-retardant outer sheath 3 is 0.15 - 3 mm.

[0097] Among them, both the radiation-resistant sheath of the sub-unit and the radiation-resistant flame-retardant outer sheath are sheaths with heat-insulating films, where:

[0098] The radiation-resistant sheath of the sub-unit includes a radiation-resistant flame-retardant sub-unit sheath material layer 7 and a crystalline polymer porous membrane layer 8;

[0099] The radiation-resistant flame-retardant outer sheath includes a radiation-resistant flame-retardant outer sheath material layer 3 and a crystalline polymer porous membrane 9;

[0100] The thickness of the radiation-resistant flame-retardant sub-unit sheath 7 is 0.15 mm; the coefficient of thermal expansion is 9×10 -7 / k.

[0101] The crystalline polymer porous membrane layer 8 has a porosity of 30 - 42%, a crystallinity of 25 - 30%, and a thickness of 10 - 15 μm; the flexural modulus is between 5 MPa and 20 MPa, and the coefficient of thermal expansion is 3 - 9×10 -7 / k. Specific parameter examples 2 - 1 to 2 - 3 adopt the technical solutions of examples 1 - 1 to 1 - 3.

[0102] The thickness of the radiation-resistant flame-retardant sub-unit sheath material layer 3 is 3.0 mm; the coefficient of thermal expansion is 9×10 -7 / k.

[0103] The crystalline polymer porous membrane layer 9 has a porosity between 35 - 42%, a crystallinity between 20 - 40%, and a thickness between 20 - 25 μm; the flexural modulus is between 5 MPa and 20 MPa, and the coefficient of thermal expansion is between 4.5×10 -7 / k - 8×10 -7 / k.

[0104] The photocurable resin coating used in this example, the porous membrane layer 8 refers to Example 1, and the composition of the crystalline polymer porous membrane layer 9 is shown in Table 2 - 1 below:

[0105] Table 2 - 1 Composition Table of Photocurable Resin Coating

[0106]

[0107]

[0108] The manufacturing method of the heat-insulating optical cable in this example is as follows:

[0109] Place 1 radiation-resistant single-mode optical fiber with a diameter of 250 μm on the pay-off reel, with a pay-off tension of 0.8 N. After being coated with a high-temperature polyacrylic resin tight jacket layer by a coater, the outer diameter is 500 μm, and then it is taken up after cooling and drying.

[0110] Extrusion: Place 1 tight-buffered optical fiber and 4 930dtex aramid fibers on the pay-off stand, with a pay-off tension of 1.5N, and only the guide wheel and the wire collection die enter the extruder extrusion subunit sheath. The extruder is sequentially arranged from the feed port to the die mouth as follows: feed port, barrel zone 1, barrel zone 2, barrel zone 3, barrel zone 4, barrel zone 5, machine neck and die mouth, and the temperature of each zone is set as follows: feed port is 130±5℃, barrel zone 1 is 135±10℃, barrel zone 2 is 140±10℃, barrel zone 3 is 145±10℃, barrel zone 4 is 150±10℃, barrel zone 5 is 155±10℃, machine neck and die mouth are 160±10℃; the cooling area arranged at the die mouth outlet adopts segmented cooling, the first cooling section connected to the die mouth adopts a warm water cooling tank with a cooling temperature of 50±10℃, and the remaining sections are cooled by normal temperature water.

[0111] Coating: The sub-unit pay-off tension is below 5N, and the temperature is controlled between 40-60℃ after being heated in an oven. After entering the entrance die, it is light-cured and coated with a layer of light-curing coating with a thickness of 15um, and then the wire is collected after passing through the exit die.

[0112] Hole forming: The sub-unit after winding is passed through a heat preservation furnace, and an axial tension of 3N is applied through a screening guide wheel for stretching. The temperature of the heat preservation furnace is 80°C, and the cured high-temperature resistant membrane is subjected to a hole forming treatment for 10s.

[0113] Two 1.8mm optical fiber sub-units and two 1.8mm filling ropes are passed through the guide wheel and the line collection mold into the twisting table for twisting, and the twisting pitch is 500mm. Finally, a layer of radiation-resistant flame-retardant sheath with a thickness of 3.0mm is extruded by the sheath extruder. The extruder is arranged in order from the feed port to the die as follows: feed port, barrel zone 1, barrel zone 2, barrel zone 3, barrel zone 4, barrel zone 5, machine neck and die, and the temperature of each zone is set as follows: feed port is 130±5°C, barrel zone 1 is 135±10°C, barrel zone 2 is 140±10°C, barrel zone 3 is 145±10°C, barrel zone 4 is 150±10°C, barrel zone 5 is 155±10°C, and neck and die are 160±10°C; the cooling area arranged at the die outlet adopts segmented cooling, the first cooling section connected to the die adopts a warm water cooling tank with a cooling temperature of 50±10°C, and the remaining sections are cooled by normal temperature water.

[0114] Coating: The cable pay-off tension is below 20N, and the temperature is controlled between 40-60℃ after being heated in an oven. After entering the entrance die, it is light-cured and coated with a layer of light-curing coating with a thickness of 15um to 20um, and then it is reeled in after passing through the exit die.

[0115] Hole forming: The collected optical cable is passed through a heat preservation furnace and stretched by applying an axial tension of 48N through a screening guide wheel. The temperature of the heat preservation furnace is 100°C, and the cured high-temperature resistant film is subjected to hole forming treatment for 30s.

[0116] For the heat-insulating optical cable manufactured in this embodiment, the structure and performance test results of the crystalline polymer porous membrane layer 9 of the radiation-resistant and flame-retardant outer sheath are shown in Table 2-2 below:

[0117] Table 2-2

[0118]

[0119]

[0120] For the heat-insulating optical cable manufactured in this embodiment, the heat-insulating effect test method is as follows: Measure the deformation time of the tight-buffered optical fiber at 125°C. The results show that no deformation occurred in Examples 2-1 to 2-3, while deformation occurred in Comparative Example 2-1 after 60 hours, and immediate deformation occurred in Comparative Example 1-2. This shows that for the heat-insulating optical cable prepared in this embodiment, the heat-insulating effect of the crystalline polymer porous membrane is obvious, and the high-temperature resistance of the optical cable is significantly improved under its action.

[0121] It is easy for those skilled in the art to understand that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A heat-insulating optical cable, characterized in that, The optical unit sheath and / or the outer sheath of the optical cable is a sheath with a heat insulation film; The sheath with a heat insulation film includes a tightly combined sheath material layer and a crystalline polymer porous film; the crystalline polymer is a high-temperature resistant photocurable resin; The crystalline polymer porous film has a porosity of 30%-50%; a crystallinity of 20-40%; a thickness between 5-25 μm; and an average pore diameter between 2-4 μm; The peel force between the sheath material layer and the crystalline polymer porous film is between 10 N and 50 N.

2. The heat-insulating optical cable according to claim 1, characterized in that, The crystalline polymer porous film has a porosity of 30%-42%; a crystallinity of 25-30%; and a thickness between 10-20 μm.

3. The heat-insulating optical cable according to claim 1, wherein The bending modulus of the crystalline polymer porous film is between 5 MPa and 20 MPa, and its thermal expansion coefficient matches that of the sheath material layer.

4. The heat-insulating optical cable according to claim 3, wherein The bending modulus of the crystalline polymer porous film is between 8 MPa and 15 MPa.

5. The heat-insulating optical cable according to any one of claims 1 to 4, characterized in that, The crystalline polymer is one or a combination of polyphenylene sulfide resin, polyether ether ketone, polyether ketone, and polyimide.

6. The heat-insulating optical cable according to any one of claims 1 to 4, characterized in that The crystalline polymer contains a nucleating agent with a mass fraction between 8-12%.

7. The heat-insulating optical cable according to claim 6, wherein The nucleating agent contains dip-coated chitosan.

8. The heat-insulating optical cable according to claim 6, characterized in that, A polyvinyl alcohol film-forming system is adopted.

9. The heat-insulating optical cable according to claim 1, wherein, The thickness ratio between the sheath material layer and the crystalline polymer porous film is between 20-500:

1.

10. The heat-insulating optical cable according to claim 1, wherein The optical unit sheath is a loose tube or an optical fiber tight jacket layer.

11. The heat-insulating optical cable according to claim 1, characterized in that, The outer sheath of the optical cable is a sheath with a heat insulation film; The sheath material layer is made of anti-irradiation low-smoke halogen-free flame-retardant polyolefin, and the crystalline polymer porous film is formed of photocured polyphenylene sulfide resin.

12. A photocurable resin coating, characterized in that, The photocurable resin precursor solution contains a film-forming agent with a mass fraction of 8-12%, and the balance is the photocurable resin precursor matrix solution; The film-forming agent includes, by mass: 50 to 80 parts of a volatile solvent, 10-20 parts of a nucleating agent, and 10 to 20 parts of a precursor monomer; The nucleating agent is dip-coated chitosan; The precursor monomer is polyvinyl alcohol.

13. The photocurable resin coating according to claim 12, wherein, The volatile solvent is N-methylpyrrolidone and / or formic acid as the solvent; The mass fraction of N-methylpyrrolidone is between 40-60 parts; The mass fraction of formic acid is between 10-20 parts.

14. The photocurable resin coating according to claim 12, wherein, The photocurable resin precursor matrix solution includes, by mass: 40~70 parts of a monomer, 5~10 parts of a plasticizer, 2~3 parts of a lubricant, 1-10 parts of a photoinitiator, and 1-10 parts of a catalyst.

15. The photocurable resin coating according to claim 14, wherein, The photocurable resin precursor matrix solution includes, by mass: 5-20 parts of inorganic particles.

16. The application of the photocurable resin coating according to any one of claims 12 to 14, characterized in that, It is applied to form a crystalline polymer porous film.

17. The application of the photocurable resin coating according to claim 16, wherein, The crystalline polymer porous film has a porosity of 30%-50%; a crystallinity of 20-40%; a thickness between 5-25 μm; and an average pore diameter between 2-4 μm.

18. The application of the photocurable resin coating according to claim 17, wherein, The crystalline polymer porous film has a porosity of 30%-42%; a crystallinity of 25-30%; and a thickness between 10-20 μm.

19. The manufacturing method of the heat-insulating optical cable according to any one of claims 1 to 11, characterized in that, Combine the components of the composite optical cable and form the optical unit sheath or the outer sheath of the optical cable according to the following method: Extrusion: Extrude the sheath material to form a sheath material layer; Coating: Maintain the temperature of the sheath material layer between 40 and 60 °C. On the outer side of the sheath material layer, sizing and coat the photocurable resin coating as described in any one of claims 12 to 15, and subject it to ultraviolet light treatment to cure the coating layer, forming a coating layer with a preset thickness to obtain a sheath preform; Pore formation: Maintain the temperature of the sheath preform at 80 - 100 °C and apply an axial tension of 2 - 50 N for a duration of 10 - 30 s, so that the coating layer of the sheath preform forms a crystalline polymer porous membrane with a porous structure.

20. The manufacturing method of the heat-insulating optical cable according to claim 19, characterized in that, The ultraviolet light treatment controls the ultraviolet light power between 0.10 - 1.0 J / cm².

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