Optical cable and preparation method thereof

Abstract

The invention discloses an optical cable and a preparation method thereof, and relates to the field of optical information. The optical cable comprises an optical unit, a first protection layer and a second protection layer. The first protection layer is arranged on the outer side of the optical unit and is used for wrapping the optical unit; the second protection layer is arranged on the side, away from the optical unit, of the first protection layer and used for wrapping the first protection layer; wherein the material of the first protective layer comprises a foamed organic material. By arranging the first protective layer formed by the foamed organic material between the optical unit and the second protective layer, on one hand, the foamed material can provide a certain stress buffering effect for the optical unit, so that the optical fiber is not easily damaged by external force, and on the other hand, certain friction force exists between the optical unit and the foamed material; on the other hand, the foaming material is easier to clean compared with the traditional fiber paste during construction, and the construction is facilitated.

Description

Technical Field

[0001] The present application relates to the field of optical information technology, and in particular to an optical cable and a method for preparing the same. Background Art

[0002] Overhead optical cables are generally laid using electric poles. They are widely used in access networks during network construction because they use existing overhead open-wire poles, save construction costs, and shorten construction periods. Overhead optical cables are hung on electric poles and are required to be able to adapt to various natural environments, such as strong winds and ice. At the same time, the design and selection of overhead optical cables should match the maximum span requirements corresponding to overhead laying.

[0003] In engineering applications, after the optical cable is laid according to certain sag requirements, it will face various external forces, such as wind, ice, bird flocks, etc. Under the action of these external forces, the optical cable will be strained and stretched. During the stretching process of the optical cable, there is a greater risk of the optical fiber being broken. Summary of the invention

[0004] The present application provides an optical cable and a preparation method thereof to solve the problem that the existing optical fiber is easily broken.

[0005] In a first aspect, the present application provides an optical cable, comprising:

[0006] Light unit;

[0007] A first protective layer is disposed on the outer side of the light unit and is used to wrap the light unit;

[0008] A second protective layer is disposed on the outside of the first protective layer and is used to wrap the first protective layer;

[0009] Wherein, the material of the first protective layer includes foamed organic material.

[0010] In traditional central tube overhead optical cables, the subunit is a loose tube filled with fiber jelly, and the optical unit is a bare optical fiber. The presence of fiber jelly can buffer the external force on the optical fiber and ensure that the optical cable can have more stable optical performance.

[0011] Since the fiber paste is liquid, when the optical cable is stretched, the friction force on the optical fiber is low. As time goes by, the optical fiber can slowly creep, and the optical fiber at the end continues to pull inward, causing the optical fiber to be broken.

[0012] In the present application, a first protective layer formed of a foamed organic material is provided between the optical unit and the second protective layer. On the one hand, the foamed material can provide a certain force buffering effect to the optical unit, so that the optical fiber is not easily damaged by external force. At the same time, there is a certain friction between the optical unit and the foamed material, so that the optical unit is not easy to twitch in the foamed material, reducing the risk of breaking the optical fiber. On the other hand, during construction, the foamed material is easier to clean than traditional fiber paste, which is convenient for construction.

[0013] It should be noted that the optical unit can be a bare optical fiber or a 0.6mm or 0.9mm tight-buffered fiber. The tight-buffered fiber sheath material is TPEE (thermoplastic polyester elastomer), which can effectively protect the optical fiber and reduce damage from the external environment. The small bending radius and excellent mechanical and environmental properties make it adaptable to various complex application environments and improve the stability and reliability of signal transmission.

[0014] In some embodiments, the organic material includes at least one of PE (polyethylene) and PVC (polyvinyl chloride). The melting points of PE and PVC are usually closer to the melting points of the commonly used second protective layer materials, so that the first protective layer and the second protective layer can be formed simultaneously in the preparation process. PE foam material has good toughness, flexibility and cushioning properties, and its closed-cell structure gives it excellent electrical insulation and heat insulation properties. PVC foam material has the characteristics of waterproofing and shock absorption, and its surface can remain loose.

[0015] In some embodiments, the density of the first protective layer is 0.1-0.6 g / cm 3 The lower the density, the larger the material pores, the smaller the weight, and the better the elastic deformation ability. The greater the density, the higher the material strength. The density of the first protective layer is within this range, which can reduce the weight of the optical cable, making it easier to install the optical cable between the poles, while providing sufficient support strength for the optical unit to protect the optical unit.

[0016] In some embodiments, the friction coefficient of the first protective layer is 0.2 to 0.6. In traditional overhead optical cables, the space between the optical unit and the sheath is filled with fiber paste, which can buffer the external force on the optical fiber and ensure that the optical cable can have relatively stable optical performance. However, there is almost no friction between the fiber paste and the optical unit, and there is almost no binding force on the optical unit. When the optical cable is stretched, the friction force on the optical fiber is low. As time goes by, the optical fiber can slowly creep, and the optical fiber at the end is constantly pulled inward, making the optical fiber end prone to breakage. The first protective layer using foam material, because the friction coefficient of the foam material is within this range, and the foam material has a certain deformation ability, can provide the optical fiber with external force absorption while fixing the optical fiber, reducing the movement of the optical fiber relative to the second protective layer, and reducing the probability of optical fiber breakage.

[0017] In some embodiments, the second protective layer includes an inner protective layer, an intermediate protective layer and an outer protective layer from the direction close to the first protective layer to the direction away from the first protective layer. By providing the inner protective layer, the intermediate protective layer and the outer protective layer, the overhead optical cable can be further protected and the damage to the overhead optical cable by the external environment can be reduced.

[0018] In some embodiments, the material of the inner protective layer includes at least one of PBT (polybutylene terephthalate), PE, and PVC. Usually, the inner protective layer is a loose tube layer, which can provide an additional protective layer for the optical fiber, reduce the mechanical stress on the optical fiber during use, thereby reducing the risk of optical fiber breakage or damage, and can also increase the mechanical strength of the optical fiber, resist damage caused by external traction or pulling, reduce the erosion of the optical fiber by the external environment such as acid, alkali, grease, moisture, etc., and ensure the stability and reliability of the optical fiber transmission signal. Under harsh environmental conditions, the loose tube layer can protect the optical fiber, reduce damage, and enable accurate transmission of key information. The optical fibers in the optical cable in the loose tube layer are loosely placed, which can protect the optical fiber from internal stress and external side pressure. It can also effectively isolate water vapor, reduce the adverse effects of water molecules on the transmission performance of the optical fiber, adapt to temperature changes under different climatic conditions, reduce the internal stress caused by differences in thermal expansion coefficients, and improve the stability of the optical fiber transmission performance. Using at least one of the above-mentioned inner protective layer materials can protect the inner protective sheath from irreversible damage when the optical cable is twisted, impacted, or flattened. And / or,

[0019] The material of the intermediate protective layer includes at least one of aramid yarn and glass yarn. Usually, the intermediate protective layer is a reinforcement yarn with high strength characteristics, which provides the necessary tensile strength for the optical cable, reduces the risk of optical fiber breakage due to external forces during the laying and use of the optical cable, and enables the optical cable to better resist external physical stresses such as stretching, extrusion and bending, thereby maintaining the structural integrity of the optical cable and the stability of the transmission performance. In extreme environments, such as deep sea or high altitude, the reinforcement yarn can ensure that the optical cable will not be damaged due to the harsh environment, ensuring the continuity and reliability of communications. Using at least one of the above-mentioned materials for the intermediate protective layer can effectively provide the optical cable with the necessary tensile strength to meet application requirements. And / or,

[0020] The material of the outer protective layer includes at least one of LSZH (low-smoke halogen-free flame retardant material), PE (polyethylene), and PVC (polyvinyl chloride). LSZH produces very little smoke and toxic gas when burning, which can improve the safety performance of wires and cables. Common low-smoke halogen-free flame retardant materials are: polyethylene, a thermoplastic resin with good electrical insulation and chemical stability. By adding flame retardants such as aluminum hydroxide or magnesium hydroxide, polyethylene can be turned into a low-smoke halogen-free flame retardant material; ethylene-vinyl acetate copolymer (EVA), a material copolymerized from ethylene and vinyl acetate, has good flexibility and processability; polypropylene, a thermoplastic resin, has good heat resistance and mechanical properties; polyolefin elastomer (POE), a polyolefin material with rubber elasticity. Thermoplastic elastomer (TPE), a material with both plastic and rubber properties, has good elasticity and wear resistance; flexible polytrimethylene terephthalate, has good heat resistance and electrical insulation. Using at least one of the above outer protective layer materials can further protect the internal components of the optical cable, so that the optical unit can adapt to various transportation, laying, and working scenarios, and has tensile, compression, and bending resistance, as well as waterproof and moisture-proof effects.

[0021] In a second aspect, the present application proposes a method for preparing an optical cable, which is used to prepare the optical cable of the first aspect of the present application, comprising the following steps:

[0022] Extruding the material of the first protective layer and the material of the second protective layer simultaneously on the surface of the light unit to form a foamed first protective layer and a foamed second protective layer respectively;

[0023] The first protective layer is located between the optical unit and the second protective layer.

[0024] By simultaneously extruding the material of the first protective layer and the material of the second protective layer from the surface of the optical unit to form a foamed first protective layer and a second protective layer, the gap between the first protective layer and the second protective layer can be made smaller, and the movement of the first protective layer relative to the second protective layer can be reduced, thereby improving the protection of the internal optical unit, further reducing the movement of the optical unit, and reducing the risk of optical fiber breakage.

[0025] In some embodiments, the extrusion temperature is 120-220° C. The extrusion temperature within this range can ensure that each material can be smoothly formed and the foaming material reaches a corresponding foaming degree.

[0026] In some embodiments, the extrusion pressure is 80-600 bar. When the extrusion pressure is within this range, a suitable foaming density can be obtained.

[0027] In some embodiments, a nucleating agent is added to the material of the first protective layer, wherein:

[0028] The nucleating agent includes at least one of diazine dicarboxylic acid amide and p-toluenesulfonyl hydrazide. Using at least one of the above nucleating agents can promote the foaming of the foaming substrate. And / or,

[0029] The mass proportion of the nucleating agent in the material of the first protective layer is 0.2-2.5%. Within this range, the mass proportion of the nucleating agent in the material of the first protective layer can make the foaming material obtain 0.1-0.6g / cm 3 density, and appropriate porosity. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 This is a schematic diagram of the optical cable laying status of the prior art of this application.

[0032] Figure 2 This is a schematic diagram of the optical cable structure of an embodiment of the optical cable of the present application.

[0033] Figure 3 This is a schematic diagram of the optical cable structure of another embodiment of the optical cable of the present application.

[0034] Description of Figure Numbers:

[0035] 100 optical cable; 1 optical unit; 2 first protective layer; 3 second protective layer; 31 inner protective layer; 32 middle protective layer; 33 outer protective layer. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

[0037] Overhead optical cables are usually laid using pole resources, such as Figure 1 As shown in the figure, it is widely used in access networks in network construction because it uses the existing overhead open-wire poles, saves construction costs, and shortens the construction period. Overhead optical cables are hung on poles and are required to adapt to various natural environments, such as strong winds and ice. At the same time, the design and selection of overhead optical cables should match the maximum span requirements corresponding to overhead laying.

[0038] In engineering applications, after the optical cable is laid according to certain sag requirements, it will face various external forces, such as wind, ice, bird flocks, etc. Under these external forces, the optical cable will be strained and stretched. During the stretching process of the optical cable, there is a greater risk of the optical fiber being broken. In order to avoid such engineering accidents, sufficient reinforcement elements are required when designing the optical cable. Secondly, there are certain requirements for the excess length of the optical fiber in the optical cable. In addition, the cable winding requirements at the link end and the optical fiber winding retention in the fiber fusion box need to be strictly implemented according to the construction requirements.

[0039] With the continuous progress of optical cable networking solutions, pre-connected overhead solutions are gradually being promoted. According to the specific overhead length, the active connectors at both ends of the optical cable are prefabricated in the factory to become prefabricated cables. At the same time, active connectors are also prefabricated at the connection between the wiring equipment (cross-connection box, fiber distribution box) and the optical cable. In this way, when laying the optical cable, there is no need to weld the optical cable on site, which greatly reduces the requirements for construction workers and improves the efficiency of optical cable laying.

[0040] However, in the pre-connection solution, there is almost no space for the optical fiber in the cable to buffer the twitching. When the laid optical cable is subjected to external force and strain, the risk of the optical fiber in the connector being pulled off is greatly increased. In order to save costs and facilitate construction, the optical cable is only coiled at one end, which further increases the risk of fiber breakage.

[0041] In view of this, the present application provides an optical cable and a preparation method thereof to solve the problem that the existing optical fiber is easily broken.

[0042] First, as Figure 2 As shown, the present application provides an optical cable 100, comprising:

[0043] Light unit 1;

[0044] A first protective layer 2 is provided on the outer side of the light unit 1 and is used to wrap the light unit;

[0045] The second protective layer 3 is arranged outside the first protective layer 2 and is used to wrap the first protective layer 2;

[0046] The material of the first protective layer 2 includes a foamed organic material.

[0047] In the conventional central tube aerial optical cable 100, the subunit is a loose tube filled with fiber jelly, and the optical unit 1 is a bare optical fiber. The presence of the fiber jelly can buffer the external force exerted on the optical fiber, ensuring that the optical cable 100 can have a relatively stable optical performance.

[0048] Since the fiber paste is liquid, when the optical cable 100 is stretched, the friction force on the optical fiber is low. As time goes by, the optical fiber can slowly creep, and the optical fiber at the end is constantly pulled inward, causing the optical fiber to be broken.

[0049] In the present application, by setting a first protective layer 2 formed of a foamed organic material between the optical unit 1 and the second protective layer 3, on the one hand, the foamed material can provide a certain force buffering effect to the optical unit 1, so that the optical fiber is not easily damaged by external forces. At the same time, there is a certain friction between the optical unit 1 and the foamed material, so that the optical unit 1 is not easy to twitch in the foamed material, reducing the risk of breaking the optical fiber. On the other hand, during construction, the foamed material is easier to clean than the traditional fiber paste, which is convenient for construction. By replacing the fiber paste with the foamed material, on the one hand, the foamed material can also absorb the deformation force, provide a buffering effect, and protect the optical fiber. On the other hand, the friction coefficient of the foamed material can relatively fix the optical fiber, reduce the creep of the optical fiber, and reduce the probability of the optical fiber breaking.

[0050] It should be noted that the optical unit 1 can be a bare optical fiber or a 0.6mm or 0.9mm tight-buffered fiber. The tight-buffered fiber sheath material is TPEE (thermoplastic polyester elastomer), which can effectively protect the optical fiber and reduce damage from the external environment. The small bending radius and excellent mechanical and environmental properties make it adaptable to various complex application environments and improve the stability and reliability of signal transmission.

[0051] In combination with the first aspect, in some embodiments provided in the present application, the organic material includes at least one of PE (polyethylene) and PVC (polyvinyl chloride), and the melting points of PE and PVC are usually closer to the melting points of the commonly used second protective layer 3 materials, so that in the preparation process, the first protective layer 2 and the second protective layer 3 can be formed at the same time. PE foam material has good toughness, flexibility and cushioning properties, and its closed-cell structure gives it excellent electrical insulation and heat insulation properties. PVC foam material has the characteristics of waterproofing, shock absorption, sound insulation, etc., and its surface can remain loose.

[0052] In combination with the first aspect, in some embodiments provided in the present application, the density of the first protective layer 2 is 0.1 to 0.6 g / cm 3 The lower the density, the larger the material pores, the smaller the weight, and the better the elastic deformation ability. The greater the density, the higher the material strength. The density of the first protective layer 2 is within this range, which can reduce the weight of the optical cable 100, making it easier to install the optical cable 100 between the poles, while providing sufficient support strength for the optical unit 1 to protect the optical unit 1. The density of the first protective layer 2 includes but is not limited to 0.1g / cm 3 , 0.2g / cm 3 , 0.3g / cm 3 , 0.4g / cm 3 , 0.5g / cm 3 or 0.6g / cm 3 .

[0053] In combination with the first aspect, in some embodiments provided in the present application, the friction coefficient of the first protective layer 2 is 0.2 to 0.6. The friction coefficient of the optical cable 100 refers to the ratio of the friction between the contact surface of the optical cable 100 and other objects during the laying process to the normal pressure perpendicular to the contact surface. In the traditional overhead optical cable 100, the space between the optical unit 1 and the sheath is filled with fiber paste, which is similar to gel and can buffer the external force on the optical fiber to ensure that the optical cable 100 can have a relatively stable optical performance. However, there is almost no friction between the fiber paste and the optical unit 1, and there is almost no binding force on the optical unit 1. When the optical cable 100 is stretched, the friction force on the optical fiber is low. As time goes by, the optical fiber can slowly creep, and the optical fiber at the end is constantly pulled inward, making the optical fiber end easy to break. The first protective layer 2 using foam material, because the friction coefficient of the foam material is within this range, and the foam material has a certain deformation ability, can provide external force absorption for the optical fiber while fixing the optical fiber, reducing the movement of the optical fiber relative to the second protective layer 3, and reducing the probability of optical fiber breakage. The friction coefficient of the first protective layer 2 includes, but is not limited to, 0.2, 0.3, 0.4, 0.5 or 0.6.

[0054] Combined with the first aspect, Figure 3 As shown, in some embodiments provided in the present application, the second protective layer 3 includes an inner protective layer 31, an intermediate protective layer 32 and an outer protective layer 33 from the direction close to the first protective layer 2 to the direction away from the first protective layer 2. By providing the inner protective layer 31, the intermediate protective layer 32 and the outer protective layer 33, the aerial optical cable 100 can be further protected and the damage to the aerial optical cable 100 by the external environment can be reduced.

[0055] In conjunction with the first aspect, in some embodiments provided in the present application, the material of the inner protective layer 31 includes at least one of PBT (polybutylene terephthalate), PE, and PVC. Usually, the inner protective layer 31 is a loose sleeve layer, and the loose sleeve layer can provide an additional protective layer for the optical fiber, reduce the mechanical stress of the optical fiber during use, thereby reducing the risk of optical fiber breakage or damage, and can also increase the mechanical strength of the optical fiber, resist the damage caused by external traction or pulling, reduce the erosion of the optical fiber by the external environment such as acid, alkali, grease, moisture, etc., and ensure the stability and reliability of the optical fiber transmission signal. Under harsh environmental conditions, the loose sleeve layer can protect the optical fiber, reduce damage, and enable accurate transmission of key information. The optical fiber in the optical cable 100 in the loose sleeve layer is loosely placed, which can protect the optical fiber from the influence of internal stress and external side pressure. It can also effectively isolate water vapor, reduce the adverse effects of water molecules on optical fiber transmission performance, adapt to temperature changes under different climatic conditions, reduce the internal stress caused by differences in thermal expansion coefficients, and improve the stability of optical fiber transmission performance.

[0056] In combination with the first aspect, in some embodiments provided in the present application, the material of the intermediate protective layer 32 includes at least one of aramid yarn and glass yarn. Typically, the intermediate protective layer 32 is a reinforcement layer having high strength characteristics, which provides the optical cable 100 with the necessary tensile strength, reduces the risk of optical fiber breakage due to external forces during the laying and use of the optical cable 100, and enables the optical cable 100 to better resist external physical stresses such as stretching, extrusion and bending, thereby maintaining the structural integrity of the optical cable 100 and the stability of the transmission performance. In extreme environments, such as deep sea or high altitude, the reinforcement yarn can ensure that the optical cable 100 will not be damaged due to the harsh environment, thereby ensuring the continuity and reliability of communication.

[0057] In some embodiments of the present application, the total density of the glass yarn in the material of the intermediate protective layer 32 can be greater than 6000 dtex, and the total density of the aramid yarn can be greater than 4000 dtex. It should be noted that in the present application, the intermediate protective layer 32 is located on the outside of the first protective layer, but not on the inside of the first protective layer. The reason is that the function of the first protective layer is to provide friction resistance for the light unit and reduce the movement of the light unit in the second protective layer. Therefore, the first protective layer needs to be in direct contact with the light unit to play a role in limiting the light unit.

[0058] In combination with the first aspect, in some embodiments provided in the present application, the material of the outer protective layer 33 includes at least one of LSZH (low smoke halogen-free flame retardant material), PE, and PVC, wherein LSZH produces very little smoke and toxic gas when burned, which can improve the flame retardant properties of wires and cables to improve safety. Common low smoke halogen-free flame retardant materials include: polyethylene, a thermoplastic resin with good electrical insulation and chemical stability. By adding flame retardants such as aluminum hydroxide or magnesium hydroxide, polyethylene can be turned into a low smoke halogen-free flame retardant material; ethylene-vinyl acetate copolymer (EVA), a material copolymerized from ethylene and vinyl acetate, has good flexibility and processability; polypropylene, a thermoplastic resin, has good heat resistance and mechanical properties; polyolefin elastomer (POE), a polyolefin material with rubber elasticity. Thermoplastic elastomer (TPE), a material with both plastic and rubber properties, has good elasticity and wear resistance; flexible polytrimethylene terephthalate, has good heat resistance and electrical insulation. The outer protective layer 33 can provide an additional protective layer for the optical fiber, reduce the mechanical stress on the optical fiber during use, thereby reducing the risk of optical fiber breakage or damage, and can also increase the mechanical strength of the optical fiber, resist damage caused by external traction or pulling, reduce the erosion of the optical fiber by the external environment such as acid, alkali, grease, moisture, etc., and ensure the stability and reliability of the optical fiber transmission signal. Under harsh environmental conditions, the second protective layer 3 can protect the optical fiber from internal stress and external side pressure. It can also effectively isolate water vapor, reduce the adverse effects of water molecules on optical fiber transmission performance, adapt to temperature changes under different climatic conditions, reduce internal stress caused by differences in thermal expansion coefficients, and improve the stability of optical fiber transmission performance.

[0059] It should be noted that the outer protective layer 33 may also be provided with a rigid reinforcement member to improve the tensile strength of the optical cable 100. The rigid reinforcement member may be steel wire, carbon fiber, or the like.

[0060] In a second aspect, the present application proposes a method for preparing an optical cable 100, which is used to prepare the optical cable 100 of the first aspect of the present application, comprising the following steps:

[0061] The material of the first protective layer 2 and the material of the second protective layer 3 are simultaneously extruded on the surface of the light unit 1 to form a foamed first protective layer 2 and a foamed second protective layer 3 respectively;

[0062] The first protective layer 2 is located between the optical unit 1 and the second protective layer 3 .

[0063] By simultaneously extruding the material of the first protective layer 2 and the material of the second protective layer 3 through the surface of the optical unit 1 to form a foamed first protective layer 2 and a second protective layer 3, the gap between the first protective layer 2 and the second protective layer 3 can be made smaller, and the movement of the first protective layer 2 relative to the second protective layer 3 can be reduced, thereby improving the protection of the internal optical unit 1, further reducing the movement of the optical unit 1, and reducing the risk of optical fiber breakage.

[0064] In conjunction with the second aspect, in some embodiments provided in the present application, the extrusion temperature is 120-220°C. Within this range, the extrusion temperature can ensure that each material can be smoothly formed and the foaming material reaches a corresponding foaming degree. The extrusion temperature includes but is not limited to 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C or 220°C.

[0065] In conjunction with the second aspect, in some embodiments provided in the present application, the extrusion pressure is 80 to 600 bar, and within this range, a suitable foaming density can be obtained. The extrusion pressure includes but is not limited to 80 bar, 100 bar, 150 bar, 200 bar, 250 bar, 300 bar, 350 bar, 400 bar, 450 bar, 500 bar, 550 bar or 600 bar.

[0066] In combination with the second aspect, in some embodiments provided in the present application, a nucleating agent is added to the material of the first protective layer 2, wherein the nucleating agent includes at least one of diazine dicarboxylic acid amide and p-toluenesulfonyl hydrazide. Using at least one of the above nucleating agents can promote the foaming of the foaming substrate.

[0067] In combination with the second aspect, in some embodiments provided in the present application, a nucleating agent is added to the material of the first protective layer 2, wherein: the mass proportion of the nucleating agent in the material of the first protective layer 2 is 0.2-2.5%. The mass proportion of the nucleating agent in the material of the first protective layer is within this range, which can make the foaming material obtain 0.1-0.6 g / cm 3 The mass percentage of the nucleating agent in the material of the first protective layer 2 includes but is not limited to 0.2%, 0.5%, 0.8%, 1.0%, 1.3%, 1.5%, 1.7%, 2.0%, 2.2% or 2.5%.

[0068] It should be noted that the thickness of each layer in the optical cable of the present application is consistent with that of a conventional optical cable, and the present application will not describe them one by one.

[0069] The technical solution of the present application will be described below in conjunction with specific embodiments.

[0070] Example 1

[0071] An optical cable, comprising:

[0072] Optical unit, 0.9mm tight-buffered fiber, the tight-buffered fiber sheath material is TPEE, and the inner side of the sheath is the optical fiber;

[0073] The first protective layer is arranged on the outside of the light unit and is used to wrap the light unit. It is a foamed PE material with a density of 0.1g / cm 3 , the friction coefficient is 0.2;

[0074] The second protective layer is arranged on the outside of the first protective layer and is used to wrap the first protective layer. The second protective layer includes an inner protective layer, a middle protective layer and an outer protective layer from the direction close to the first protective layer to the direction away from the first protective layer. The material of the inner protective layer is PBT, the material of the middle protective layer is aramid yarn, and the material of the outer protective layer is low-smoke halogen-free flame retardant material.

[0075] Example 2

[0076] An optical cable, comprising:

[0077] Optical unit, 0.6mm tight-buffered fiber, the tight-buffered fiber sheath material is TPEE, and the inner side of the sheath is the optical fiber;

[0078] The first protective layer is arranged on the outside of the light unit and is used to wrap the light unit. It is a foamed PVC material with a density of 0.4g / cm 3 , the friction coefficient is 0.4;

[0079] The second protective layer is arranged on the outside of the first protective layer and is used to wrap the first protective layer. The second protective layer includes an inner protective layer, a middle protective layer and an outer protective layer from the direction close to the first protective layer to the direction away from the first protective layer. The material of the inner protective layer is PVC, the material of the middle protective layer is glass yarn, and the material of the outer protective layer is PVC.

[0080] Example 3

[0081] An optical cable, comprising:

[0082] Optical unit, 0.9mm tight-buffered fiber, the tight-buffered fiber sheath material is TPEE, and the inner side of the sheath is the optical fiber;

[0083] The first protective layer is arranged on the outside of the light unit and is used to wrap the light unit. It is a foamed PE material with a density of 0.6g / cm 3 , the friction coefficient is 0.6;

[0084] The second protective layer is arranged on the outside of the first protective layer and is used to wrap the first protective layer. The second protective layer includes an inner protective layer, a middle protective layer and an outer protective layer from the direction close to the first protective layer to the direction away from the first protective layer. The material of the inner protective layer is PE, the material of the middle protective layer is glass yarn, and the material of the outer protective layer is PE.

[0085] Comparative Example 1

[0086] An optical cable, comprising:

[0087] Optical unit, 0.9mm tight-buffered fiber, the tight-buffered fiber sheath material is TPEE, and the inner side of the sheath is the optical fiber;

[0088] The fiber paste is arranged on the outside of the optical unit and is used to wrap the optical unit. It is in gel form.

[0089] The second protective layer is arranged on the outside of the first protective layer and is used to wrap the first protective layer. The second protective layer includes an inner protective layer, a middle protective layer and an outer protective layer from the direction close to the first protective layer to the direction away from the first protective layer. The material of the inner protective layer is PE, the material of the middle protective layer is glass yarn, and the material of the outer protective layer is PE.

[0090] Performance Testing

[0091] Take 10m of the optical cables of Examples 1-3 and Comparative Example 1, coil them with a diameter of 50cm, and coil them 5 times. Apply a 20N droop force to the optical fiber at one end through a weight. Observe the elongation of the optical fiber on the force-applying side compared with the initial state within 24 hours. The experimental results are shown in Table 1.

[0092] Table 1 Experimental results of optical cable tensile strength of Examples 1-3 and Comparative Example 1

[0093]

[0094]

[0095] As shown in Table 1, in Comparative Example 1, fiber paste is used to fill between the optical unit and the outer sheath, and the displacement within 24 hours is much greater than that of Examples 1 to 3, and as the application time of the external force increases, the displacement of the optical unit increases, and the risk of the optical unit breaking increases. This shows that using foaming material instead of fiber paste can increase the friction coefficient of the optical unit, reduce the movement of the optical unit, and play a role in fixing the optical unit.

[0096] In summary, by providing a first protective layer formed by a foamed organic material between the optical unit and the second protective layer, on the one hand, the foamed material can provide a certain force buffering effect to the optical unit, so that the optical fiber is not easily damaged by external force. At the same time, there is a certain friction between the optical unit and the foamed material, so that the optical unit is not easy to twitch in the foamed material, reducing the risk of optical fiber breaking. On the other hand, during construction, the foamed material is easier to clean than traditional fiber paste, which is convenient for construction.

[0097] In the description of this specification, the description with reference to the terms "one embodiment / method", "some embodiments / methods", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / method or example are included in at least one embodiment / method or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment / method or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments / methods or examples. In addition, those skilled in the art may combine and combine the different embodiments / methods or examples described in this specification and the features of the different embodiments / methods or examples, unless they are contradictory.

[0098] It should be noted that, in the present application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements defined by the sentence "comprise one..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements. In the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically stipulated.

[0099] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. An optical cable, characterized in that: include: Light unit; A first protective layer is disposed on the outer side of the light unit and is used to wrap the light unit; A second protective layer is disposed on the outside of the first protective layer and is used to wrap the first protective layer; Wherein, the material of the first protective layer includes foamed organic material.

2. The optical cable according to claim 1, characterized in that The organic material includes at least one of PE and PVC.

3. The optical cable according to claim 1, characterized in that The density of the first protective layer is 0.1-0.6 g / cm 3 .

4. The optical cable according to claim 1, characterized in that The friction coefficient of the first protective layer is 0.2-0.

6.

5. The optical cable according to claim 1, characterized in that The second protective layer includes an inner protective layer, a middle protective layer and an outer protective layer from a direction close to the first protective layer to a direction away from the first protective layer.

6. The optical cable according to claim 5, characterized in that: The material of the inner protective layer includes at least one of PBT, PE, and PVC; and / or, The material of the intermediate protective layer includes at least one of aramid yarn and glass yarn; and / or, The material of the outer protective layer includes at least one of LSZH, PE and PVC.

7. A method for preparing an optical cable according to any one of claims 1 to 6, characterized in that: The following steps are involved: Extruding the material of the first protective layer and the material of the second protective layer simultaneously on the surface of the light unit to form a foamed first protective layer and a foamed second protective layer respectively; The first protective layer is located between the optical unit and the second protective layer.

8. The method for preparing an optical cable according to claim 7, characterized in that: The extrusion temperature is 120-220°C.

9. The method for preparing an optical cable according to claim 7, characterized in that: The extrusion pressure is 80-600 bar.

10. The method for preparing an optical cable according to claim 7, characterized in that: A nucleating agent is added to the material of the first protective layer, wherein: The nucleating agent includes at least one of diazine dicarboxylic acid amide and p-toluenesulfonyl hydrazide; and / or, The mass proportion of the nucleating agent in the material of the first protective layer is 0.2-2.5%.

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