Low-smoke-density high-temperature-resistant halogen-free special flame-retardant optical cable

Abstract

The invention discloses a low-smoke-density high-temperature-resistant halogen-free special flame-retardant optical cable, which comprises a cable core, an inner sheath and a fireproof layer from inside to outside, and is characterized in that the fireproof layer comprises a fireproof layer made of a ceramic silicone rubber material; the cable core comprises optical fibers, a loose tube, a reinforcing piece and an internal flame-retardant thermal insulation layer, the reinforcing piece is located in the center of the cable core, the optical fibers are arranged in the loose tube to form an optical fiber unit and surround the reinforcing piece, the internal flame-retardant thermal insulation layer comprises water-blocking yarn and a calcined mica tape, and the space between the optical fiber unit and the reinforcing piece is filled with the water-blocking yarn. And the optical fiber units, the reinforcers and the water-blocking yarns are wound by the calcined mica tape in a multi-layer and multi-pitch manner. According to the invention, the ceramic silicone rubber material is adopted and is ceramized in a flame state or at a high temperature of more than 500 DEG C to form an oxygen barrier layer, so that a flashover phenomenon in the cable is prevented; ointment is removed from the structure, and the water-blocking yarn and the calcined mica tape are used for blocking water, so that smoke in the combustion process is reduced, and the harm to personnel is less under the condition of fire hazard.

Description

Technical Field

[0001] The patent of this invention relates to a low smoke density, high temperature resistant, halogen-free special flame retardant optical cable, belonging to the technical field of flame retardant optical cables. Background Art

[0002] As one of the important pillars of modern communications, optical fiber is widely used in technical fields such as the Internet of Things, biosensors, virtual reality, AI, and the fifth generation of mobile communications. Generally, one or more optical fibers wrapped in a sheath are used as the medium to form a component of a communication cable. The laying environment faced during the cable laying process is very complex. It often needs to pass through mountains, forests, towns and other areas. When the optical fiber passes through the above-mentioned areas, due to the harsh environment, the maintenance cost is high, and it is difficult for firefighting forces to reach in the event of a fire. In this case, the communication status of the optical fiber is often easily affected, and signal blocking may occur in severe cases. Therefore, under certain circumstances, it is necessary to improve the structure of the existing optical cable so that it has a stronger fireproof capability in the face of special situations such as fires to avoid communication interruptions. Summary of the invention

[0003] The purpose of this patent is to provide a low smoke density, high temperature resistant, halogen-free special flame retardant optical cable to solve the fire prevention problem in the above technical background.

[0004] The technical scheme for achieving the purpose of the present invention is: a low smoke density, high temperature resistant, halogen-free special flame retardant optical cable, comprising a cable core, an inner sheath and a fireproof layer arranged from the inside to the outside, wherein the fireproof layer comprises a fire-resistant layer, and the fire-resistant layer is made of ceramic silicone rubber material; the cable core comprises an optical fiber, a loose tube, a reinforcement member and an internal flame retardant thermal insulation layer, wherein the reinforcement member is located at the center of the cable core, the optical fiber is arranged inside the loose tube to form an optical fiber unit and surrounds the reinforcement member, the internal flame retardant thermal insulation layer comprises a water-blocking yarn and a calcined mica tape, the optical fiber unit and the reinforcement member are filled with water-blocking yarn, and the calcined mica tape is used to perform multi-layer pitch winding of the optical fiber unit, the reinforcement member and the water-blocking yarn.

[0005] The fire-resistant layer of a low-smoke-density, high-temperature-resistant, halogen-free special flame-retardant optical cable of the present invention adopts a ceramic silicone rubber material. Based on the characteristics of ceramic materials, the material will quickly harden and gradually ceramicize into a dense, hard and dense ceramic shell oxygen-isolating layer under flame conditions or at high temperatures above 500°C, thereby preventing flashover from occurring inside the cable. The material selected for the fire-resistant layer is a methyl rubber matrix filled with allyl cyclotriphosphazene and magnesium hydroxide and other high flame retardants to form the required composite rubber. After being radiated with gamma rays, its own flame retardant properties and mechanical properties are improved, and it is used to replace traditional halogen flame retardants. During the combustion process, no toxic colored gas is generated, but silica particles and water are The purpose of flame retardancy and self-extinguishing can be achieved, and the strength of the oxygen-isolating layer of the ceramic shell is greatly increased. No cracks will appear after the temperature is lowered. In the subsequent repair process, it is only necessary to remove the refractory layer and cover it with new material. This process does not require re-laying of cables, which can greatly reduce the difficulty of post-disaster maintenance. After testing, the cables prepared by this scheme can withstand high temperatures of 1200°C to 1600°C. The flame-retardant optical cable structure of the present invention removes the grease, and uses water-blocking yarn and calcined mica tape as the water-blocking structure. The calcined mica tape uses a composite material of high-temperature resistant phlogopite paper and artificial synthetic mica, and uses glass fiber blended cloth and polyester to replace traditional glass fiber cloth, so as to better enhance the flexibility and tensile strength of the mica tape. The surface treatment process of the water-blocking yarn requires the use of adhesive, aluminum ammonium salt, alcohol and deionized water in a ratio of 1:3:6:4 to obtain a reagent. The reagent is coated on the water-blocking yarn and then dried in an oven at high temperature to obtain high-efficiency water-blocking yarn for optical cables. It effectively improves the undesirable phenomena such as powder sticking and dampness on the surface of the water-blocking yarn. While ensuring the water-blocking effect, it can effectively reduce the smoke generated during the combustion of the ointment, and has less harm to personnel in the event of a fire.

[0006] Further or optionally, the inner sheath adopts low-smoke halogen-free oxygen-isolating flame retardant material, and the sheath material is made of a base material of zinc hydroxystannate and doped with magnesium hydroxide and calcium carbonate particles to prepare a clay-based flame retardant nanocomposite material. By using the flame retardant effect of nanoparticles on silicone rubber materials, a stronger and more efficient halogen-free flame retardant and smoke suppression optimized design is obtained, so that less smoke is generated in the event of a fire, and in the event of a fire, it can effectively prevent people around from being choked by smoke and causing infection.

[0007] Further or optionally, the fireproof layer is composed of a highly flame-retardant glass fiber tape, a steel tape and a fireproof layer from the inside to the outside. The glass fiber tape used in the optical cable includes a first glass fiber silk layer and a second glass fiber silk layer, and an anti-cracking layer and an aramid composite layer are also adhered between the two silk layers. The glass fiber tape is subjected to electron beam coating curing irradiation in a nitrogen atmosphere to be effectively fixed, thereby preventing the glass fiber tape from spreading and winding, and facilitating subsequent use. There is a progressive relationship between the fireproof temperatures of the inner and outer layers, which can effectively prevent high temperatures from penetrating the fireproof layer, effectively prevent flame invasion during the combustion of the optical cable, and effectively improve the mechanical effect of the optical cable.

[0008] Further or optionally, the reinforcement is formed by twisting a variety of fibers such as glass fiber, carbon fiber, and aramid fiber, and the water-blocking yarn adopts a three-layer twisting process with close winding at positive and negative angles. This can effectively reduce the weight of the reinforcement while ensuring its strength. The three-layer twisting process with close winding at positive and negative angles adopted by the water-blocking yarn can effectively ensure its water-blocking effect. The two are combined with each other to effectively waterproof the cable core structure while supporting it.

[0009] Further or optionally, the calcined mica tape is subjected to a vacuum treatment after winding, so that a vacuum state is formed between the cable core and the inner sheath, so that an air isolation zone can be formed between the calcined mica tape and the inner sheath, which effectively isolates heat and slows down the combustion process.

[0010] The glass fiber tape fireproof layer is a three-layer structure, in which the two layers close to the inner protective layer are wound in the opposite direction to the outer layer. This structure can prevent high-temperature gas from entering the inner layer through the winding gap, thereby achieving better fireproof effect.

[0011] The steel belt is a copolymer coated steel belt, which is coated with green and transparent copolymers on both sides, has a hardness of T2 level, and has good formability and plasticity. The material has good bonding with the steel belt after surface coating and has chemical resistance and high temperature resistance. The substrate used is a low-carbon electroplated chrome steel belt to obtain better reflection effect and reduce the amount of heat radiation inside the optical cable.

[0012] The copolymer coated steel belt is bonded to the hard and highly flame-retardant glass fiber belt by high temperature resistant glue to avoid fixation failure due to high temperature.

[0013] By adopting the above technical solution, the present invention has the following beneficial effects:

[0014] (1) The fire-resistant layer of a low-smoke-density, high-temperature-resistant, halogen-free special flame-retardant optical cable of the present invention adopts a ceramic silicone rubber material. Based on the characteristics of ceramic materials, the material will quickly harden and gradually ceramicize into a dense, hard and dense ceramic shell oxygen-isolating layer under flame conditions or at a high temperature of more than 500°C, thereby preventing the occurrence of flashover inside the cable. The material selected for the fire-resistant layer is a methyl rubber matrix filled with allyl cyclotriphosphazene and magnesium hydroxide and other high flame retardants to form the required composite rubber. After being irradiated with gamma rays, its own flame retardant properties and mechanical properties are improved, and it is used to replace traditional halogen flame retardants. No toxic colors will be produced during the combustion process. The flame retardant and self-extinguishing purpose can be achieved not only by colored gas but also by silica particles and water. The strength of the oxygen barrier layer of the ceramic shell is greatly increased. No cracks will appear after the temperature is lowered. In the subsequent repair process, it is only necessary to remove the refractory layer and cover it with new material. This process does not require re-laying of cables, which can greatly reduce the difficulty of post-disaster maintenance. After testing, the cables prepared by this scheme can withstand high temperatures of 1200℃ to 1600℃. The structure of the optical cable removes the ointment and adopts water-blocking yarn and calcined mica tape as the water-blocking structure. While ensuring the water-blocking effect, it can effectively reduce the smoke generated during the combustion of the ointment, and poses less harm to personnel in the event of a fire.

[0015] (2) The inner sheath is made of low-smoke, halogen-free, oxygen-isolating, flame-retardant material, which produces less smoke in the event of a fire and can effectively prevent people around from being choked by smoke and becoming infected.

[0016] (3) The fireproof layer of the present invention is a three-layer structure of a highly flame-retardant glass fiber belt, a steel belt and a fire-resistant layer from the inside to the outside, which can effectively prevent the flame from invading during the combustion process of the optical cable and effectively improve the mechanical effect of the optical cable.

[0017] (4) The reinforcement of the present invention is made of glass fiber, carbon fiber, and aramid fiber. The water-blocking yarn adopts a three-layer twisting process with positive and negative angles. This can effectively reduce the weight of the reinforcement while ensuring its strength. The three-layer twisting process with positive and negative angles adopted by the water-blocking yarn can effectively ensure its water-blocking effect. The two are combined with each other to effectively waterproof the cable core structure while supporting it.

[0018] (5) After the calcined mica tape of the present invention is wound, a vacuum treatment is performed, and a vacuum state is formed between the cable core and the inner sheath. In this way, an air isolation zone can be formed between the calcined mica tape and the inner sheath, which effectively isolates heat and slows down the combustion process.

[0019] (6) The fireproof layer of the glass fiber tape of the present invention is a three-layer structure, in which the two layers close to the inner protective layer are wound in the opposite direction to the outer layer. This structure can prevent high-temperature gas from entering the inner layer through the winding gap, thereby obtaining a better fireproof effect.

[0020] (7) The steel strip of the present invention is made of double-sided chrome-plated material. The material itself has a reflective effect and can effectively reflect heat to protect the inner structure of the optical cable.

[0021] (8) The highly flame-retardant glass fiber tape and the steel tape of the present invention are bonded together by high-temperature resistant glue to avoid fixation failure due to high temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments and in conjunction with the accompanying drawings, wherein

[0023] Figure 1 It is a structural schematic diagram of the present invention.

[0024] The numbers in the accompanying drawings are: cable core 1, optical fiber 11, loose tube 12, reinforcement 13, internal flame retardant insulation layer 14, water-blocking yarn 141, calcined mica tape 142, inner sheath 2, fireproof layer 3, fire-resistant layer 31, high flame retardant glass fiber tape 32, steel tape 33. DETAILED DESCRIPTION

[0025] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0029] In the description of the embodiments of the present invention, it should be understood that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is conventionally placed when used, or are the orientations or positional relationships conventionally understood by those skilled in the art. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0030] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The present invention is further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the scope of protection of the present invention.

[0031] (Example 1)

[0032] See Figure 1 The embodiment of the present invention is a low smoke density, high temperature resistant, halogen-free special flame retardant optical cable, comprising a cable core 1, an inner sheath 2 and a fireproof layer 3 arranged from the inside to the outside, wherein the fireproof layer 3 comprises a fireproof layer 31, and the fireproof layer 31 is made of ceramic silicone rubber material.

[0033] The reinforcement 13 is formed by twisting glass fiber, carbon fiber, aramid fiber and other fibers, and the water-blocking yarn 141 is twisted by a three-layer twisting process with positive and negative angles.

[0034] The calcined mica tape 142 is subjected to vacuum treatment after being wound, so that a vacuum state is formed between the cable core 1 and the inner sheath 2 .

[0035] The fire-resistant layer 31 is a fire-resistant ceramic silicone rubber outer sheath, and special modifiers, high-efficiency halogen-free flame retardants and ultraviolet absorbers are added to enhance its performance.

[0036] The cable core 1 includes an optical fiber 11, a loose tube 12, a reinforcement member 13 and an internal flame retardant and thermal insulation layer 14. The reinforcement member 13 is located at the center of the cable core 1. The optical fiber 11 is arranged inside the loose tube 12 to form an optical fiber unit and surrounds the reinforcement member 13. The internal flame retardant and thermal insulation layer 14 includes a water-blocking yarn 141 and a calcined mica tape 142. The water-blocking yarn 141 is used to fill the space between the optical fiber unit and the reinforcement member 13. The calcined mica tape 142 is used to wind the optical fiber unit, the reinforcement member 13 and the water-blocking yarn 141 in multiple layers with different pitches.

[0037] The calcined mica tape 5 used in the present invention has high flexibility, a smooth surface, and high temperature resistance, and can be used for fireproofing and heat insulation inside the high temperature resistant optical cable, thereby enhancing the stable signal transmission performance of the fire resistant optical cable.

[0038] In the event of a fire, based on the characteristics of ceramic silicone rubber materials, it will quickly harden and gradually ceramicize under flames or at high temperatures above 500°C, forming a hard and dense ceramic shell oxygen-isolating layer, which prevents internal explosions. It can withstand continuous high temperatures of 1200°C to 1600°C, and abandons traditional grease inside the cable core. It uses a semi-dry structure design that only uses dry water-blocking materials such as water-blocking yarn and calcined tape to reduce the smoke generated when the optical cable burns.

[0039] The water-blocking yarn 141 and the calcined mica tape 142 in the structure not only meet the water seepage requirements, but also avoid the combustion-supporting effect of the cable paste on the optical cable and the influence of a large amount of smoke generated when the paste burns.

[0040] The fireproof layer 3 is composed of a highly flame-retardant glass fiber tape 32, a steel tape 33 and a fireproof layer 31 from the inside to the outside. The glass fiber tape fireproof layer 32 is a three-layer structure, in which the two layers close to the inner protective layer 2 are wound in the opposite direction to the outer layer. The steel tape 33 is made of double-sided chrome-plated material, and the highly flame-retardant glass fiber tape 32 and the steel tape 33 are bonded by high-temperature resistant glue. The thickness of the steel tape 33 is 0.13mm, the nominal thickness of the plastic composite layer on the surface is about 0.05mm, the coating bonding strength is greater than 7N, and the chromium coating content on the surface of the steel tape is 0.16g / m 2 The steel belt is armored and longitudinally wrapped, and high temperature resistant glue is added before longitudinal wrapping. The steel belt 33 and the inner high flame retardant glass fiber belt 32 are adhered to each other at a pitch of 1:10 and three layers of densely wound inner sheath 2, so that the inner layer is isolated from open flames, and the flame invasion is slowed down during the burning process of the optical cable, and the mechanical properties of the optical cable are improved.

[0041] The inner sheath 2 is made of low-smoke, halogen-free, oxygen-isolating and flame-retardant material.

[0042] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A low smoke density, high temperature resistant, halogen-free special flame retardant optical cable, characterized by: The invention comprises a cable core (1), an inner sheath (2) and a fireproof layer (3) arranged from the inside to the outside, wherein the fireproof layer (3) comprises a fireproof layer (31), and the fireproof layer (31) is made of a ceramic silicone rubber material; the cable core (1) comprises an optical fiber (11), a loose tube (12), a reinforcing member (13) and an internal flame retardant and thermal insulation layer (14), wherein the reinforcing member (13) is located at the center of the cable core (1), the optical fiber (11) is arranged inside the loose tube (12) to form an optical fiber unit and surrounds the reinforcing member (13), and the internal flame retardant and thermal insulation layer (14) comprises a water-blocking yarn (141) and a calcined mica tape (142), the water-blocking yarn (141) is used to fill the space between the optical fiber unit and the reinforcing member (13), and the calcined mica tape (142) is used to wind the optical fiber unit, the reinforcing member (13) and the water-blocking yarn (141) in multiple layers with different pitches.

2. The low smoke density, high temperature resistant, halogen-free special flame retardant optical cable according to claim 1, characterized in that: The inner sheath (2) is made of low-smoke, halogen-free, oxygen-isolating and flame-retardant material.

3. The low smoke density, high temperature resistant, halogen-free special flame retardant optical cable according to claim 1, characterized in that: The fireproof layer (3) comprises, from the inside to the outside, a highly flame-retardant glass fiber tape (32), a steel tape (33) and a fireproof layer (31).

4. The low smoke density, high temperature resistant, halogen-free special flame retardant optical cable according to claim 1, characterized in that: The reinforcing member (13) is formed by twisting a plurality of fibers including glass fiber, carbon fiber and aramid fiber, and the water-blocking yarn (141) is twisted by a three-layer twisting process with positive and negative angles.

5. The low smoke density, high temperature resistant, halogen-free special flame retardant optical cable according to claim 1, characterized in that: The calcined mica tape (142) is subjected to a vacuum treatment after being wound, so that a vacuum state is formed between the cable core (1) and the inner sheath (2).

6. The low smoke density, high temperature resistant, halogen-free special flame retardant optical cable according to claim 3, characterized in that: The glass fiber tape fireproof layer (32) is a three-layer structure, wherein the two layers close to the inner protective layer (2) are wound in the opposite direction to the outer layer.

7. The low smoke density, high temperature resistant, halogen-free special flame retardant optical cable according to claim 3, characterized in that: The steel strip (33) is made of a double-sided chrome-plated material.

8. The low smoke density, high temperature resistant, halogen-free special flame retardant optical cable according to claim 3, characterized in that: The highly flame-retardant glass fiber tape (32) and the steel tape (33) are bonded together by high-temperature resistant glue.

Images