Low-temperature molded air-blowing optical cable suitable for high-temperature installation operation environment

Abstract

The invention discloses a low-temperature molded air-blowing optical cable suitable for a high-temperature installation operation environment. The low-temperature molded air-blowing optical cable comprises a sheath and a cable core with a sleeve, the cable core is accommodated in the sheath, and a sleeve of the cable core is in contact with the sheath; the sheath is made of a polyvinyl thermoplastic material and contains a cycloolefin copolymer; the Vicat softening point of the sheath ranges from 60 DEG C to 90 DEG C, the sheath is formed through extrusion processing, and the extrusion processing temperature of the sheath is lower than the melting point temperature of the sleeve. According to the low-temperature molded air-blowing optical cable suitable for the high-temperature installation operation environment, the thermodynamic property of the outer layer material of the sheath is optimized, so that the sheath material has good basic processing performance on the premise that the sheath material has a lower friction coefficient in the high-temperature installation operation environment; the adverse effect on the shape stability of the sleeve caused by the increase of the extrusion processing temperature after the outer layer material of the sheath is optimized is solved, the air-blowing laying distance at high temperature is increased, the consistency of the excess length is kept, and the transmission loss is improved.

Description

Technical Field

[0001] The present invention belongs to the field of optical communication, and more specifically, relates to a blown optical cable suitable for high-temperature installation operation environment and formed at low temperature. Background Art

[0002] The technical principle of the blown microtube optical cable for blown laying communication is to use an air compressor to compress air and inject it into the communication pipeline, forming a high-pressure and high-speed air flow in the communication pipeline. The air flow drives the optical cable to move rapidly in the microtube, achieving the purpose of rapid optical cable laying.

[0003] Long-term experimental exploration shows that during construction in summer, the laying distance of the blown optical cable is significantly shortened. To overcome this problem, the Chinese patent application with the application number 202211636746.2 uses a sheath material with a relatively high softening point to reduce the frictional resistance borne by the blown optical cable during high-temperature installation operations.

[0004] However, after using the sheath material with a relatively high softening point, it is observed that the length consistency of the blown optical cable decreases and the transmission loss increases. Summary of the Invention

[0005] In view of the above defects or improvement requirements of the prior art, the present invention provides a blown optical cable suitable for high-temperature installation operation environment and formed at low temperature. The purpose is to simultaneously optimize the softening point temperature and melt flow index of the polyethylene-based sheath through cycloolefin copolymer, so as to maintain the extrusion processing temperature not exceeding the melting point temperature of the sleeve in contact with the sheath while increasing the softening point temperature, and avoid secondary shrinkage crystallization due to the sheath forming process, thereby improving the length consistency and avoiding the increase of transmission loss, and thus solving the technical problem of increased transmission loss of the existing high-temperature resistant blown optical cable.

[0006] To achieve the above object, according to one aspect of the present invention, there is provided a blown optical cable suitable for high-temperature installation operation environment and formed at low temperature, including a sheath and a cable core with a sleeve;

[0007] The cable core is received in the sheath, and its sleeve is in contact with the sheath;

[0008] The sheath is a polyethylene-based thermoplastic material containing cycloolefin copolymer;

[0009] The Vicat softening point of the sheath is between 60°C and 90°C, and it is formed by extrusion processing, and its extrusion processing temperature is lower than the melting point temperature of the sleeve.

[0010] Preferably, in the blown optical cable suitable for high-temperature installation operation environment and formed at low temperature, the cycloolefin copolymer is a non-crystalline resin formed by copolymerization of norbornene and ethylene.

[0011] Preferably, for the blowable optical cable formed at low temperature and applicable to high-temperature installation working environments, the molar proportion of norbornene is between 30% and 50%, and the glass transition temperature of the cycloolefin copolymer is between 75°C and 160°C.

[0012] Preferably, for the blowable optical cable formed at low temperature and applicable to high-temperature installation working environments, the polyethylene-based thermoplastic material used for the sheath has a melt flow index greater than 0.4 g under a load of 2.16 kg at 190°C.

[0013] Preferably, for the blowable optical cable formed at low temperature and applicable to high-temperature installation working environments, the polyethylene-based thermoplastic material used for the sheath contains a cycloolefin copolymer with a mass fraction between 5% and 12%.

[0014] Preferably, for the blowable optical cable formed at low temperature and applicable to high-temperature installation working environments, the polyethylene-based thermoplastic material used for the sheath contains high-density polyethylene, and the mass ratio of it to the cycloolefin copolymer is between (80 - 92):(5 - 12), and the degree of polymerization distribution of the high-density polyethylene is between 2000 and 10000.

[0015] Preferably, for the blowable optical cable formed at low temperature and applicable to high-temperature installation working environments, the polyethylene-based thermoplastic material used for the sheath contains silicone masterbatch, and the mass ratio of it to the cycloolefin copolymer is between (1 - 3):(5 - 12).

[0016] Preferably, for the blowable optical cable formed at low temperature and applicable to high-temperature installation working environments, the polyethylene-based thermoplastic material used for the sheath contains functional masterbatch, and the mass ratio of it to the cycloolefin copolymer is between (2 - 5):(5 - 12); the functional masterbatch is selected from one or more of linear low-density polyethylene, antioxidants and antioxidant aids, light stabilizers and light stabilizer aids, and carbon black.

[0017] Preferably, for the blowable optical cable formed at low temperature and applicable to high-temperature installation working environments, the sleeve uses a crystalline material, the melting point of the material is greater than 215°C, and the crystallization temperature point of the material is in the range greater than 160°C.

[0018] Preferably, for the blowable optical cable formed at low temperature and applicable to high-temperature installation working environments, the extrusion processing temperature of the sheath is between 160°C and 200°C.

[0019] Generally speaking, compared with the prior art through the above technical solutions conceived by the present invention, the following beneficial effects can be achieved:

[0020] The low-temperature forming air-blown optical cable applicable to high-temperature installation operation environment provided by the present invention optimizes the thermodynamic properties of the outer layer material of the sheath, so that the sheath material has a lower friction coefficient in the high-temperature installation operation environment, and at the same time has good basic processing properties. The Vicat softening point temperature of its material is between 60°C and 90°C, and the sheath material still has a relatively high melt flow index. Without changing the extrusion processing temperature basically, it meets the thermodynamic property requirements of the air-blown micro cable applicable to the high-temperature installation operation environment, solves the adverse impact on the shape stability of the sleeve caused by the increase of the extrusion processing temperature after the optimization of the outer layer material of the sheath, improves the air-blown laying distance at high temperature, maintains the consistency of the surplus length, and improves the transmission loss.

[0021] The present invention adopts adding cycloolefin copolymer in the sheath mixture, which can not only optimize the thermodynamic properties of the sheath including the softening point temperature and the melt flow index, but also multiply improve the puncture resistance strength of the thin-wall sheath, which is more conducive to the thin-wall extrusion of the air-blown micro cable sheath, and at the same time achieves the purpose of increasing the core density of the optical cable.

[0022] The present invention does not need to particularly consider the influence of the construction working environment temperature, broadens the construction window period, and makes the popularization and application of the air-blown laying technology more easily acceptable; it solves the limitation of the application area of the air-blown optical cable. Whether it is in summer or winter, it can be constructed. Whether it is used in cold regions in the Northern Hemisphere or tropical regions in the Southern Hemisphere, as long as it is air-blown in the same specification pipeline, the same air-blown optical cable product can be used without multiple product developments. Description of the Drawings

[0023] Figure 1 is the standard needle adopted by the penetration test method of the present invention;

[0024] Figure 2 is a schematic diagram of a central tube optical cable;

[0025] Figure 3 is a schematic diagram of an air-blown pipeline.

[0026] Figure 4 is a schematic diagram of the optical cable being air-blown in the pipeline

[0027] Figure 5 is the glass transition temperature diagram of cycloolefin in the embodiment; wherein Figure 5 A is the glass transition temperature analysis diagram of the cycloolefin copolymer with the molar proportion of norbornene about 50%, Figure 5 B is the glass transition temperature analysis diagram of the cycloolefin copolymer with the molar proportion of norbornene about 30%;

[0028] Figure 6It is the DSC diagram of the sheath material in Example 1 (corresponding to Curve 1 in the figure), the DSC diagram of the sheath material in Example 4 (corresponding to Curve 2 in the figure), and the DSC diagram of the sheath material in Comparative Example 5 (corresponding to Curve 3 in the figure).

[0029] Figure 7 It is the DSC diagram of the sheath material in Example 2 (corresponding to Curve 4 in the figure) and the DSC diagram of the sheath material in Example 3 (corresponding to Curve 5 in the figure).

[0030] In all the drawings, the same reference numerals are used to represent the same elements or structures, where: 1 is the pressure seat, 2 is the standard needle, 3 is the optical fiber, 4 is the sleeve, 5 is the aramid reinforcement, 6 is the sheath, 7 is the main and driven wheels of the air blower, 8 is the blown cable, 9 is the air flow, and 10 is the pipeline. Detailed implementation manners

[0031] In order to make the objectives, technical solutions and advantages of the present invention clearer, 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 embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0032] Sheath materials generally having a relatively high softening point temperature have a higher extrusion processing temperature during extrusion molding than the existing sheath materials. Most of the existing sleeve materials are crystalline materials. The melting point of the typical sleeve material PBT is about 225°C. If the extrusion processing temperature of the sheath material is higher than the melting point and crystallization temperature point of the sleeve material, it will cause the sleeve material to undergo secondary crystallization shrinkage, significantly affecting the surplus length of the optical cable, resulting in a decrease in the surplus length consistency and an increase in transmission loss. The more the extrusion processing temperature of the sheath material is higher than the melting point of the sleeve material, the more obvious the influence is, and the attenuation of the optical cable in high and low temperature environments becomes uncontrollable, affecting the performance of the optical cable.

[0033] The blown optical cable with low-temperature molding and suitable for high-temperature installation operation environments provided by the present invention includes a sheath and a cable core having a sleeve; the cable core is received in the sheath, and its sleeve is in contact with the sheath;

[0034] The sheath is a polyvinyl-based thermoplastic material containing a cycloolefin copolymer;

[0035] The Vicat softening point of the sheath is between 60°C and 90°C, and it is formed by extrusion processing, and its extrusion processing temperature is lower than the melting point temperature of the sleeve.

[0036] The sheath material used for the sheath is a high molecular thermoplastic material with a Vicat softening point between 60°C and 90°C. Typically, it is a high-density polyethylene material, and its Vicat softening point can be adjusted according to the polymerization degree distribution. The higher the degree of high molecular polymerization and the larger the proportion, the higher the Vicat softening point. At the same time, to ensure good extrusion effect at a lower processing temperature, a material with a higher softening point is added to the sheath in a certain proportion. The penetration of the sheath material is below 1.25 mm within the range of 10°C to 70°C, preferably between 0.95 and 1.25 mm. At the same time, for every 10°C increase in temperature, the penetration of the sheath material increases by no more than 0.1 mm with the increase in temperature. The penetration at 25°C does not exceed 1.0 mm. In particular, the penetration at 40°C to 60°C does not exceed 1.15 mm, preferably:

[0037] The penetration at 40°C does not exceed 1.1 mm; the penetration at 50°C does not exceed 1.13 mm; the penetration at 60°C does not exceed 1.14 mm.

[0038] The test method for the above penetration: Place a 3-mm thick pressed sheet in a temperature cycling chamber, hold it at the test temperature point for 4 hours, apply a 50-N tension with a standard needle tip on the surface of the sheet for 5 seconds, and measure the depth (mm) of penetration into the sheet. As shown in Figure 1, the standard needle, the specification refers to the needle tip in the material hardness test method, see "National Standard of the People's Republic of China GB-T2411-2008 Plastics and Hard Rubber - Determination of Indentation Hardness (Shore Hardness) by Means of a Durometer".

[0039] The sheath is in contact with the sleeve, providing protection for the sleeve. For blown optical cables, the cable core can be a stranded cable core with a sleeve or a central tube cable core with a sleeve. As shown in Figure 2, the blown optical cable has the characteristics of high fiber density and a compact structural design. Generally, there is contact between the sleeve and the sheath. During the manufacturing process, this compact structural design causes the temperature of the extruded material of the sheath to directly affect the cable core with a sleeve. When using a rigid polyethylene material with a high degree of polymerization, a relatively high extrusion processing temperature is required, and the sleeve material is heated, resulting in secondary crystallization shrinkage. Refer to the Chinese patent application with the application number 202211636746.2. The polyethylene-based material commonly used for the optical cable sheath can control the Vicat softening point by adding modifiers or adjusting the degree of polymerization of polyethylene. However, the polyethylene-based material within the range of the modified softening point has a relatively high melting point, generally above 130°C. To ensure the fluidity of the extruded material during extrusion molding, the extrusion working temperature is increased compared to the extrusion processing temperature of the existing sheath, generally above 220°C, and even above 230°C. Through repeated experimental exploration, the secondary crystallization shrinkage of the crystallized sleeve material is an important reason for the unstable excess length and increased transmission loss of the blown optical cable with a rigid sheath suitable for high-temperature installation working environments. The sheath of this patent uses a polyethylene-based thermoplastic material, and the thermodynamic properties of the polyethylene-based thermoplastic material are optimized by adding a cycloolefin copolymer. On the one hand, the softening point of the sheath material can be increased, and on the other hand, while increasing the melt flow index of the sheath material, the extrusion processing temperature remains almost unchanged.

[0040] The cycloolefin copolymer is a copolymer of norbornene and ethylene, which is randomly embedded in the main chain of the ethylene polymer. Therefore, it can be melt-blended with polyethylene, such as HDPE, in any proportion and has good compatibility. No adhesives and phase solvents are required. By adjusting the content of norbornene in the polymer, such as controlling the molar ratio of norbornene in the polymer between 30% and 50%, a cycloolefin copolymer with a glass transition temperature of 75°C - 170°C is formed. Since the molecule of norbornene is larger than that of ethylene, the glass transition temperature increases with the increase in the ratio of norbornene in the main chain. Based on this principle, the heat resistance of the polyolefin resin mixture is adjusted. However, while increasing the softening point of the blown microcable sheath through the cycloolefin copolymer, the sheath material still has a relatively high melt flow index, meeting the thermodynamic property requirements of the blown microcable in a high-temperature installation working environment at a relatively low processing temperature.

[0041] The sheath is made of a polyethylene-based thermoplastic material containing a cycloolefin copolymer and is formed by extrusion processing. The extrusion processing temperature is lower than the melting point temperature of the sleeve. The polyethylene-based thermoplastic material used for the sheath has a melt flow index greater than 0.4 g under a load of 2.16 kg at 190°C. Preferably, the cycloolefin copolymer is an amorphous resin formed by copolymerizing norbornene and ethylene. The glass transition temperature of the cycloolefin copolymer is greater than 75°C. In a preferred embodiment, the molar ratio of norbornene is between 30% and 50%, and the glass transition temperature of the cycloolefin copolymer is between 75°C and 160°C.

[0042] In addition, during the processing of blown microcables, the wall thickness of the sheath of the current layer-stranded blown microcables is basically about 0.5 mm. To improve the utilization rate of pipeline resources and the core density, the wall thickness of the sheath is approaching the lower limit of 0.3 mm during actual production. For central tube blown microcables, the wall thickness of some sheaths is only about 0.15 mm. The complex working environment in the existing optical cable production makes it easy for ash layers to adhere to the cable core, the binding yarn joints on the cable core, and the protrusions on the surface of the sleeve to cause processing defects in the thin-walled sheath, such as pinholes, etc. Such defects are intolerable during the blowing process, otherwise it will cause the "skin explosion" phenomenon during the blowing process. Therefore, the present invention can effectively alleviate related problems.

[0043] The mass components of a typical sheath material are as follows: the mass fraction of high-density polyethylene is 80 to 92 parts, and the mass fraction of the cycloolefin copolymer is 5 to 12 parts; in a preferred embodiment, the sheath mixture contains 1 to 3 parts by mass of a silicone masterbatch. The silicone masterbatch is not a liquid organosilicon plastic additive, but a granular material formed by dispersing more than 30% of ultra-high molecular weight (UHMW) silicone oxide polymer in a polyethylene carrier. The polyethylene carrier can be LDPE or HDPE, preferably LDPE, which can make the sheath material have good fluidity at a lower processing temperature and at the same time have an excellent low friction coefficient; the sheath mixture contains 2 to 5 parts by mass of a functional masterbatch, and the functional masterbatch is selected from one or more of linear low-density polyethylene, antioxidants and antioxidant aids, light stabilizers and light stabilizer aids, and carbon black.

[0044] Adding a silicone masterbatch, this high-concentration ultra-high molecular weight (UHMW) silicone oxide polymer not only enables the sheath to have an extremely low friction coefficient, which can greatly increase the blowing distance of the microcable product, improve the construction efficiency, and reduce the construction cost, but also can avoid the problem of the increase in the friction coefficient of the sheath caused by the long-term storage of the optical cable.

[0045] In the process of preparing the polyethylene sheath, adding liquid silicone plastic additives to improve the lubricity and fluidity of thermoplastics is a very economical and common method in the industry. Such additives are effective in improving better mold filling, less extrusion torque, internal lubrication, die release, and faster throughput of the extruder, as well as the surface smoothness of the sheath. However, as the sheath of the blown micro-cable, such additives are very harmful. The blowing performance of the blown micro-cable is one of the key concerns. As the storage time of the optical cable prolongs, small molecule substances such as silicone oil in such additives will gradually migrate to the surface of the sheath, which not only cannot reduce the friction coefficient but will gradually increase the friction coefficient, and this phenomenon is not what we want. By using polyethylene as the carrier, especially a high-concentration ultra-high molecular weight (UHMW) siloxane polymer with high-density polyethylene as the carrier, not only can we achieve the desired effect of reducing the friction coefficient of the optical cable sheath, but also we don't have to worry about the risk of small molecule substances precipitating, and at the same time, it can also increase the softening point temperature of the sheath.

[0046] The sleeve is made of a crystalline material with a melting point greater than 215°C and a crystallization temperature point greater than 160°C, such as PBT for example.

[0047] The blown optical cable with low-temperature forming and suitable for high-temperature installation working environment provided by the present invention can be of a stranded or central tube structure, or other structural forms.

[0048] The preparation method of the blown optical cable with low-temperature forming and suitable for high-temperature installation working environment provided by the present invention includes the following steps:

[0049] 1) Select a cycloolefin copolymer with a glass transition temperature of 75°C - 160°C; or copolymerize norbornene and ethylene, and by adjusting the content of norbornene in the polymer, preferably the molar ratio of norbornene is 30% - 50%, to form a cycloolefin copolymer with a glass transition temperature of 75°C - 160°C.

[0050] 2) Mix the carbon black powder, antioxidant powder and additives, light stabilizer powder and additives, and LLDPE carrier powder evenly in a high-speed mixer, transfer the evenly mixed powder mixture to a twin-screw extruder for mixing, and then successively through extrusion, cooling, granulation, and drying to obtain the functional masterbatch of the sheath material. The extrusion processing temperature of the twin-screw extruder is 140°C - 190°C;

[0051] 3) Mix the cycloolefin copolymer, high-density polyethylene, silicone masterbatch, and functional masterbatch in a low-speed mixer in a certain proportion until evenly mixed. Transfer the evenly mixed mixture powder into a twin-screw extruder for kneading, and then successively through extrusion, cooling, pelletizing, and drying to obtain the micro-cable resistant to high-temperature environment air blowing and its polyethylene sheath material. The extrusion processing temperature of the twin-screw extruder is 160°C - 200°C.

[0052] The mass composition ratio of each component of the sheath is preferably: 80 - 92 parts of high-density polyethylene, 5 - 12 parts of cycloolefin copolymer, 1 - 3 parts of silicone masterbatch, and 2 - 5 parts of functional masterbatch.

[0053] 4) Extrude the above sheath material on the outer surface of the air-blown micro-cable core to form an air-blown micro-cable product applicable to high-temperature environment air blowing.

[0054] The following are examples:

[0055] The functional masterbatch used in the examples was prepared according to the following method:

[0056] Take 23 kg of low-density polyethylene powder LLDPE7042, 0.5 kg of BASF antioxidant 1010, 0.25 kg of BASF antioxidant auxiliary agent 168, and 1.25 kg of carbon black powder. Mix them in a high-speed mixer for one minute. Knead, extrude, cool, pelletize, dry, and package the above evenly mixed raw materials through a twin-screw extrusion unit at a temperature of 140 - 190 degrees to obtain the functional masterbatch.

[0057] Example 1

[0058] For the sheath material prepared in this example, take 80 kg of high-density polyethylene with a softening point of 60°C and a polymerization degree of about 2000 - 3000, 12 kg of cycloolefin copolymer with a norbornene molar ratio of about 30% and a Tg temperature of about 77°C in the raw material, 3 kg of silicone masterbatch, and 5 kg of functional masterbatch. Mix them in a low-speed mixer for 5 minutes. Knead, extrude, cool, pelletize, dry, and package the above evenly mixed raw materials through a twin-screw extrusion unit at a temperature of 160 - 200 degrees to obtain it.

[0059] Example 2

[0060] For the sheath material prepared in this example, take 92 kg of high-density polyethylene with a softening point of 60°C and a polymerization degree of about 2000 - 3000, 5 kg of cycloolefin copolymer with a norbornene molar ratio of about 50% and a Tg temperature of about 142°C in the raw material, 1 kg of silicone masterbatch, and 2 kg of functional masterbatch. Mix them in a low-speed mixer for 5 minutes. Knead, extrude, cool, pelletize, dry, and package the above evenly mixed raw materials through a twin-screw extrusion unit at a temperature of 160 - 200 degrees to obtain it.

[0061] Example 3

[0062] For the sheath material prepared in this example, 92 kg of high-density polyethylene with a softening point of 60°C and a polymerization degree of about 2000 - 3000 is taken, 5 kg of cycloolefin copolymer with a norbornene molar proportion of about 30% and a Tg temperature of about 77°C in the raw materials, 2 kg of silicone masterbatch, and 3 kg of functional masterbatch are mixed in a low-speed mixer for 5 minutes. The above uniformly mixed raw materials are kneaded, extruded, cooled, pelletized, dried, and packaged through a twin-screw extrusion unit at a temperature of 160 - 200°C to obtain the product.

[0063] Example 4

[0064] For the sheath material prepared in this example, 80 kg of high-density polyethylene with a softening point of 60°C and a polymerization degree of about 2000 - 3000 is taken, 12 kg of cycloolefin copolymer with a norbornene molar proportion of about 50% and a Tg temperature of about 142°C in the raw materials, 3 kg of silicone masterbatch, and 5 kg of functional masterbatch are mixed in a low-speed mixer for 5 minutes. The above uniformly mixed raw materials are kneaded, extruded, cooled, pelletized, dried, and packaged through a twin-screw extrusion unit at a temperature of 160 - 200°C to obtain the product.

[0065] Comparative Example 5

[0066] The sheath material prepared in this comparative example also has a relatively high softening point; 80 kg of high-density polyethylene with a softening point of 60°C and a polymerization degree of about 2000 - 3000 is taken, 12 kg of high-density polyethylene with a softening point of 90°C and a polymerization degree of about 12000 - 16000, 3 kg of silicone masterbatch, and 5 kg of functional masterbatch are mixed in a low-speed mixer for 5 minutes. The above uniformly mixed raw materials are kneaded, extruded, cooled, pelletized, dried, and packaged through a twin-screw extrusion unit at a temperature of 160 - 200°C to obtain the product.

[0067] The samples of the above Examples 1 - 5 were tested, and their main technical indicators are shown in Table 1:

[0068] Table 1 Sheath Material Performance

[0069]

[0070] For the sheath materials of Examples 1 to 4, at a load of 2.16 kg and a temperature of 190°C, the melt flow index is greater than 0.4 g, while for Comparative Example 5, the melt flow index is less than 0.4 g. The extrusion processing temperature of Examples 1 to 4 can be controlled below 220°C.

[0071] The glass transition temperature analysis of the cycloolefin copolymers used in Examples 1 to 4 is as Figure 5 shown; the DSC diagrams of the sheath materials of Examples 1, 4, and Comparative Example 5 are as Figure 6 shown; the DSC diagrams of the sheath materials of Examples 2 and 3 are as Figure 7as shown

[0072] Extrude the sheath material of the said embodiment on the surface of the same cable core to form a blown micro-optical cable with the same structure, as Figure 2 shown: The outer diameter of the optical cable is 2.4 mm, and its composition includes a composite polyethylene sheath 6, a sleeve 4 inside the sheath, and an aramid strengthening member 5 between the sheath and the sleeve. The sleeve contains optical fibers 3.

[0073] Perform the friction coefficient test of these micro-cables at laboratory temperature in the same pipeline specification 5 / 3.5. The blowing principle is as Figure 4 shown. The test results are shown in Table 2:

[0074] Table 2 Sheath parameters

[0075]

[0076] Table 3 is a comparison of the results of the influence of the sheath materials in Examples A / B / C / D and Comparative Example E of the present invention on the surplus length of the optical cable.

[0077] Table 3 Influence of sheath materials on the surplus length of the optical cable

[0078]

[0079] Table 4 is a comparison of the results of the influence of the sheath materials in Examples A / B / C / D and Comparative Example E of the present invention on the surplus length of the optical cable

[0080] Table 4 Influence of the surplus length of the optical cable on attenuation in Examples and Comparative Examples at 20 °C

[0081]

[0082] Those skilled in the art can easily 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 principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A low-temperature formed blowing optical cable applicable to high-temperature installation operation environment, Characterized in that, It includes a sheath and a cable core with a sleeve; The cable core is accommodated in the sheath, and its sleeve is in contact with the sheath; The sheath is a polyethylene-based thermoplastic material containing a cycloolefin copolymer; The Vicat softening point of the sheath is between 60°C and 90°C, and it is formed by extrusion processing, and its extrusion processing temperature is lower than the melting point temperature of the sleeve.

2. The low-temperature formed blowing optical cable applicable to high-temperature installation operation environment according to claim 1, Characterized in that, The cycloolefin copolymer is an amorphous resin formed by copolymerization of norbornene and ethylene.

3. The low-temperature formed blowing optical cable applicable to high-temperature installation operation environment according to claim 2, Characterized in that, The molar proportion of norbornene is between 30% - 50%, and the glass transition temperature of the cycloolefin copolymer is between 75°C - 160°C.

4. The low-temperature formed blowing optical cable applicable to high-temperature installation operation environment according to claim 2, Characterized in that, The polyethylene-based thermoplastic material used for the sheath has a melt flow index greater than 0.4 g under a load of 190°C and 2.16 kg.

5. The low-temperature formed blowing optical cable applicable to high-temperature installation operation environment according to claim 1, Characterized in that, The polyethylene-based thermoplastic material used for the sheath contains a cycloolefin copolymer with a mass fraction between 5% - 12%.

6. The low-temperature formed blowing optical cable applicable to high-temperature installation operation environment according to claim 1, Characterized in that, The polyethylene-based thermoplastic material used for the sheath contains high-density polyethylene, and the mass ratio of it to the cycloolefin copolymer is between (80 - 92):(5 - 12), and the degree of polymerization distribution of the high-density polyethylene is between 2000 - 10000.

7. The low-temperature formed blowing optical cable applicable to high-temperature installation operation environment according to claim 1, Characterized in that, The polyethylene-based thermoplastic material used for the sheath contains a silicone masterbatch, and the mass ratio of it to the cycloolefin copolymer is between (1 - 3):(5 - 12).

8. The low-temperature formed blowing optical cable applicable to high-temperature installation operation environment according to claim 1, Characterized in that, The polyethylene-based thermoplastic material used for the sheath contains a functional masterbatch, and the mass ratio of it to the cycloolefin copolymer is between (2 - 5):(5 - 12); the functional masterbatch is selected from one or more of linear low-density polyethylene, antioxidant and antioxidant auxiliary, light stabilizer and light stabilizer auxiliary, and carbon black.

9. The low-temperature formed blowing optical cable applicable to high-temperature installation operation environment according to claim 1, Characterized in that, The sleeve is made of a crystalline material, its material melting point is greater than 215°C, and its material crystallization temperature point is greater than 160°C.

10. The low-temperature formed blowing optical cable applicable to high-temperature installation operation environment according to claim 1, Characterized in that, The extrusion processing temperature of the sheath is between 160°C - 200°C.

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