WO2024088438A1

WO2024088438A1 - All-dielectric fire-resistant optical fibre cable and preparation method therefor

Info

Publication number: WO2024088438A1
Application number: PCT/CN2023/136620
Authority: WO
Inventors: 吴斌华; 秦浩; 周旻浩; 韩宇峰; 吴杰; 吴来强; 毛庆生; 薄双商; 沈冬; 张萍; 倪建莉; 杨明
Original assignee: 江苏亨通光电股份有限公司
Priority date: 2022-10-28
Filing date: 2023-12-06
Publication date: 2024-05-02
Also published as: CN115524817A

Abstract

An all-dielectric fire-resistant optical cable comprises a cable core, a cladding layer and a jacket structure. The cable core comprises a non-metallic central reinforcing member (1) and several unit cables, wherein each unit cable is wrapped in a first ceramicized mica tape (6); and each unit cable comprises a loose tube, and optical fibers (2) and a water barrier (3) arranged in the loose tube, and the loose tube comprises an inner tube (4) and an outer tube (5). The cladding layer comprises a water blocking tape (7), a second ceramicized mica tape(8) and a heat insulating tape (9), which are sequentially wrapped around the cable core. The jacket structure comprises an inner jacket (10) and an outer jacket (13), wherein a third ceramicized mica tape(11) is provided between the inner jacket (10) and the outer jacket (13) in a cladding manner. The all-dielectric fire-resistant optical fibre cable of the present invention can effectively prevent lightning and resist electromagnetic interference, has an excellent fire-resistant performance, has a light weight per unit of mass, has desirable flexibility, and is convenient to lay and mount.

Description

A kind of all-dielectric fire-resistant optical cable and its preparation method

Technical Field

The present invention belongs to the technical field of communication optical cables, and in particular relates to an all-dielectric fire-resistant optical cable and a preparation method thereof.

Background technique

Optical cable is a communication line that uses a certain number of optical fibers to form a cable core in a certain way, which is covered with a sheath or an outer sheath to transmit optical signals. That is, it is a cable formed by optical fibers (optical transmission carriers) through a certain process. The basic structure of an optical cable is generally composed of a cable core, reinforcing steel wires, fillers, and sheaths. In addition, there are waterproof layers, buffer layers, insulated metal wires, and other components as needed. As society's demand for communication information continues to increase, optical cables, as the infrastructure for communication information, have been widely used in data centers, communication rooms, power facilities, airports, subways, and other places.

The traditional fire-resistant optical cable structure generally forms a stable cable core structure by twisting multiple optical units around the central reinforcement and coating with water-blocking tape. After longitudinally coating with steel tape outside the water-blocking tape, a low-smoke, halogen-free flame-retardant inner sheath is extruded outside the cable core, and a flame-retardant outer sheath is extruded after coating with steel tape again. The schematic diagram of the cross-section of the optical cable is shown in Figure 1: the cable core structure includes a central reinforcement 4', multiple optical fiber groups twisted around the central reinforcement 1', and a filling rope 6' with the same outer diameter as the optical fiber group. The optical fiber group includes a loose tube 1' and an optical fiber 2' and a fiber paste 3' arranged in the loose tube 1'; the cable core structure is filled with cable paste 5' and coated with a layer of inner steel tape 7', and a sheath structure is arranged outside the inner steel tape 7'. The sheath structure includes an inner sheath A 8', an outer sheath A 10', and an outer steel tape 9' arranged between the inner sheath A 8' and the outer sheath A 10'. Although this fire-resistant optical cable can meet the fire protection needs of the above-mentioned places to a certain extent, it is a metal armored structure, which not only has poor lightning protection and electromagnetic interference resistance capabilities, but also has a heavy unit mass and a large bending radius of the optical cable, making it difficult to lay and install.

The invention patent with application number 201711287426.X discloses a lightweight non-metallic flame-retardant fire-resistant optical cable, which includes: a cable core, a fire-resistant layer wrapped around the outer periphery of the cable core, and a low-smoke halogen-free sheath layer wrapped around the outer periphery of the fire-resistant layer. The fire-resistant layer is a double-sided synthetic mica tape or a polyimide composite tape. The polyimide composite tape is a ceramic Porcelain polyimide composite tape, the thickness of the polyimide composite tape is 0.12-0.2mm, and the overlap width of the polyimide composite tape is 3-5mm. The invention patent with application number 201811177842.9 provides a fire-resistant optical cable, which includes a cable core, a water-blocking tape coated on the outside of the cable core, a double-sided synthetic mica tape coated on the outside of the water-blocking tape, an armor layer coated on the outside of the double-sided synthetic mica tape, and a sheath coated on the outside of the armor layer. The above scheme also does not consider the problem of anti-electromagnetic interference and the fire resistance performance reaching the grade. Therefore, it is necessary to design an optical cable that can effectively protect against lightning, anti-electromagnetic interference and excellent fire resistance, while meeting the requirements of light unit weight, good flexibility of the optical cable, and easy laying and installation.

Summary of the invention

The present invention aims to solve the problems that existing fire-resistant optical cables have poor lightning protection and electromagnetic interference resistance, heavy unit weight, large cable bending radius, and are difficult to construct, and provides a full-dielectric fire-resistant optical cable and a preparation method thereof.

According to the technical solution of the present invention, the all-dielectric fire-resistant optical cable comprises a cable core, a coating layer and a sheath structure.

The cable core includes a non-metallic central reinforcement and a plurality of unit cables twisted around the non-metallic central reinforcement; the unit cables are wrapped with a first ceramic mica tape, the unit cables include a loose tube and an optical fiber and a water-blocking material arranged in the loose tube, the loose tube includes an inner tube and an outer tube, the inner tube is a thermoplastic tube, and the outer tube is a fire-resistant tube;

The coating layer sequentially coats the water-blocking tape, the second ceramic mica tape and the insulation tape of the cable core, and the sheath structure is arranged outside the coating layer;

The sheath structure comprises an inner sheath and an outer sheath, and a third ceramic mica tape is coated between the inner sheath and the outer sheath.

The fire-resistant optical cable of the present invention adopts a full dielectric non-metallic structure, the loose tube adopts a double-layer structure, and the outer part of the loose tube and the double protective layers are coated with a ceramic mica tape. Under a high-temperature flame, the cable can be ablated into a hard shell residue, which is a pure ceramic inorganic substance, with a residual amount of more than 70% and will not fall off. The bending fracture strength of the shell residue is 7-12MPa.

Furthermore, the optical fiber is a bulk fiber or a ribbon fiber, wherein the ribbon fiber includes a curlable spider web ribbon fiber; The water-blocking material is fiber paste, optical fiber water-blocking tape or water-blocking yarn.

Furthermore, the inner sleeve is made of PBT (polybutylene terephthalate), PET (polyethylene terephthalate) or PP (polypropylene) material; and its wall thickness is 0.28-0.30 mm.

Furthermore, the outer sleeve is made of ceramic refractory material with a wall thickness of 0.22-0.25 mm, a tensile strength of 5-10 MPa, and an elongation at break of 100%-200%.

Furthermore, the thermal insulation belt adopts nano aerogel thermal insulation material, and the cable core is coated with nano aerogel thermal insulation material, which has extremely low thermal conductivity. At an average temperature of 800°C, its thermal conductivity is 0.052W/k·m.

Furthermore, the thickness of the thermal insulation belt is 0.45-0.50 mm, and the overlap range is 0.8-1.2 mm.

Furthermore, the overlap rates of the first ceramic mica tape, the second ceramic mica tape and the third ceramic mica tape are all 40%-50%; the thickness of the first ceramic mica tape and the second ceramic mica tape is 0.08-0.12 mm, and the thickness of the third ceramic mica tape is 0.16-0.24 mm.

Furthermore, the inner sheath is made of low-smoke halogen-free ceramic polyolefin material with a wall thickness of 1.6-2.0 mm; the outer sheath is made of highly flame-retardant low-smoke halogen-free polyolefin material with a wall thickness of 1.8-2.2 mm.

Furthermore, a non-metallic auxiliary reinforcement is provided between the third ceramic mica tape and the outer sheath.

Specifically, the non-metallic auxiliary reinforcement may be made of aramid yarn, glass fiber yarn/tape, fiber-reinforced composite material, etc.

Another aspect of the present invention provides a method for preparing the above-mentioned all-dielectric fire-resistant optical cable, characterized in that it comprises the following steps:

S1: Extruding the raw material of the inner layer casing and the raw material of the outer layer casing simultaneously outside the optical fiber and the water blocking material wrapping the optical fiber to form a unit cable;

S2: wrapping ceramic mica tape around the unit cable;

S3: twisting a number of unit cables wrapped with ceramic mica tape around a non-metallic central reinforcement to form a cable core;

S4: wrapping a water-blocking tape, a second ceramic mica tape and an insulating tape around the cable core in sequence to obtain a stable cable core structure;

S5: extruding an inner sheath outside the stable cable core structure;

S6: wrapping a ceramic mica tape around the inner sheath and placing a non-metallic auxiliary reinforcement member;

S7: Extruding a layer of outer sheath outside the non-metallic auxiliary reinforcement member to obtain the all-dielectric fire-resistant optical cable.

The technical solution of the present invention has the following advantages over the prior art: the fire-resistant optical cable of the present invention adopts an all-dielectric non-metallic structure, has the effects of lightning protection, anti-electromagnetic interference and excellent fire resistance, and at the same time, has a light unit weight, good flexibility of the optical cable, and is easy to lay and install; it is provided with multiple layers of ceramic materials, which can not only play a flame retardant and heat insulating role, but also can form a hard ceramic armor at high temperature, which plays a role in fixing, protecting and bearing vibration for the optical unit, and meets the fire resistance requirements of the optical cable; the use of nano aerogel insulation material can provide more efficient thermal insulation performance compared to conventional insulation materials; aerogel composite materials do not burn, and while being flame retardant, they also meet environmental protection requirements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the structure of a conventional fire-resistant optical cable.

FIG. 2 is a schematic diagram of the structure of the all-dielectric fire-resistant optical cable of the present invention.

Description of reference numerals: 1'-loose tube, 2'-optical fiber, 3'-fiber paste, 4'-central strength member, 5'-cable paste, 6'-filling rope, 7'-inner steel belt, 8'-inner sheath A, 9'-outer steel belt A, 10'-outer sheath;
1-non-metallic central reinforcement, 2-optical fiber, 3-water blocking material, 4-inner sleeve, 5-outer sleeve, 6-first ceramic mica tape, 7-water blocking tape, 8-second ceramic mica tape, 9-insulation tape, 10-inner sheath, 11-third ceramic mica tape, 12-non-metallic auxiliary reinforcement, 13-outer sheath.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

Example

As shown in Figure 2: All-dielectric fire-resistant optical cable, including cable core, coating layer and sheath structure.

The cable core includes a non-metallic central reinforcement member 1 and a plurality of unit cables twisted around the non-metallic central reinforcement member 1. The non-metallic central reinforcement member 1 is made of FRP. The unit cable includes a loose tube and a plurality of optical fibers 2 and water-blocking materials 3 arranged in the loose tube. The optical fibers 2 are loose fibers or ribbon fibers. The water-blocking materials 3 are made of fiber paste or water-blocking materials. The yarn/tape is filled between the optical fiber 2 and the loose tube; the loose tube adopts a double-layer structure, the inner tube 4 adopts a thermoplastic material PBT with a thickness of 0.3 mm, and the outer tube 5 adopts a ceramic refractory material with a thickness of 0.24 mm. The first ceramic mica tape 6 is wrapped around the unit cable.

The coating layer comprises a water-blocking tape 7, a second ceramic mica tape 8 and an insulating tape 9 which are sequentially coated on the outside of the cable core. The insulating tape 9 is made of nano-aerogel insulating material.

The sheath structure adopts double sheaths, the inner sheath 10 is low-smoke halogen-free ceramic polyolefin material, and the outer sheath 13 is highly flame-retardant low-smoke halogen-free polyolefin material; a third ceramic mica tape 11 with excellent fire resistance is coated between the inner and outer sheaths, and a non-metallic auxiliary reinforcement 12 is placed, and the non-metallic auxiliary reinforcement 12 is made of glass fiber yarn.

The preparation process is as follows:

(1) The optical fibers are released from the pay-off frame and the pay-off tension of the optical fibers is kept constant. After the optical fibers are coated with fiber paste, the raw materials of the inner layer and the outer layer are simultaneously extruded from the die head through a loose tube extruder and a diverter cone inside the loose tube extruder to form a double-layer loose tube;

After the loose tube is dried on the surface in the cooling area, it is wrapped with ceramic mica tape at a tension of 1N through the wrapping equipment. The overlap rate of the mica tape is controlled at 40%-50%, and the thickness is 0.1mm. It is then collected into a reel.

(2) The non-metallic center reinforcement is placed at the center, and the loose tube is twisted, and the water-blocking tape and ceramic mica tape are wrapped, and the overlap range of the mica tape is 40%-50% and the thickness is 0.10 mm; a layer of nano-aerogel insulation tape is longitudinally wrapped outside the mica tape, and the thickness of the insulation tape is 0.48 mm, and the overlap range is 1.0 mm. The optical unit and the coating material are tied together longitudinally using a wrapping machine to form a stable cable core structure;

(3) The sheath adopts a double sheath structure; the inner sheath is made of low-smoke halogen-free ceramic polyolefin material with a wall thickness of 1.8 mm; the outer sheath is made of highly flame-retardant low-smoke halogen-free polyolefin material with a wall thickness of 2.0 mm; ceramic mica tape is wrapped between the inner and outer sheaths, and glass fiber yarn or other non-metallic auxiliary reinforcements are placed; the ceramic mica tape wrapping overlap rate is 40%-50%, and the thickness is 0.20 mm.

Comparative Example 1

The first ceramic mica tape 6 , the second ceramic mica tape 8 and the third ceramic mica tape 11 are not included on the basis of Example 1.

Comparative Example 2

The embodiment 1 does not include the insulating belt 9.

Comparative Example 3

On the basis of Example 1, the outer sleeve 5 and the inner sheath 10 are replaced with common flame retardant materials.

Result analysis

The optical cables obtained in Example 1 and Comparative Examples 1-3 were subjected to fire resistance tests, and the results are shown in Table 1.

Table 1

The results show that the all-dielectric fire-resistant optical cable of the present invention has good fire-resistant performance.

In summary, compared with traditional metal structure fire-resistant optical cables, the all-dielectric fire-resistant optical cable of the present invention has the advantages of lightning protection, anti-electromagnetic interference, good flexibility, and light weight because there is no metal structure in the optical cable. In addition, the fire resistance performance of the all-dielectric optical cable is improved through structural design and material selection.

Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

A full-dielectric fire-resistant optical cable, characterized in that it comprises a cable core, a coating layer and a sheath structure,

The cable core comprises a non-metallic central reinforcement member (1) and a plurality of unit cables twisted around the non-metallic central reinforcement member (1); the unit cables are wrapped with a first ceramic mica tape (6); the unit cables comprise a loose tube and an optical fiber (2) and a water-blocking material (3) arranged in the loose tube; the loose tube comprises an inner tube (4) and an outer tube (5); the inner tube (4) is a thermoplastic tube, and the outer tube (5) is a fire-resistant tube;

The coating layer sequentially coats the water blocking tape (7), the second ceramic mica tape (8) and the insulation tape (9) of the cable core, and the sheath structure is arranged outside the coating layer;

The sheath structure comprises an inner sheath (10) and an outer sheath (13), and a third ceramicized mica tape (11) is coated between the inner sheath (10) and the outer sheath (13).
The all-dielectric fire-resistant optical cable according to claim 1 is characterized in that the optical fiber (2) is a loose fiber or a ribbon fiber; and the water-blocking material (3) is a fiber paste, an optical fiber water-blocking tape or a water-blocking yarn.
The all-dielectric fire-resistant optical cable according to claim 1 is characterized in that the inner sleeve (4) is made of PBT, PET or PP material; and the outer sleeve (5) is made of ceramic fire-resistant material.
The all-dielectric fire-resistant optical cable according to claim 1 or 3, characterized in that the wall thickness of the inner sleeve (4) is 0.28-0.30 mm, and the wall thickness of the outer sleeve (5) is 0.22-0.25 mm.
The all-dielectric fire-resistant optical cable according to claim 1, characterized in that the thermal insulation belt (9) is made of nano aerogel thermal insulation material.
The all-dielectric fire-resistant optical cable according to claim 1 or 5, characterized in that the thickness of the insulation belt (9) is 0.45-0.50 mm and the overlap range is 0.8-1.2 mm.
The all-dielectric fire-resistant optical cable according to claim 1 is characterized in that the overlap rates of the first ceramic mica tape (6), the second ceramic mica tape (8) and the third ceramic mica tape (11) are all 40% to 50%; the thickness of the first ceramic mica tape (6) and the second ceramic mica tape (8) is 0.08-0.12 mm, and the thickness of the third ceramic mica tape (11) is 0.16-0.24 mm.
The all-dielectric fire-resistant optical cable according to claim 1 is characterized in that the inner sheath (10) is a low-smoke halogen-free ceramic polyolefin material with a wall thickness of 1.6-2.0 mm; the outer sheath (13) is a highly flame-retardant low-smoke halogen-free polyolefin material with a wall thickness of 1.8-2.2 mm.
The all-dielectric fire-resistant optical cable according to claim 1 is characterized in that a non-metallic auxiliary reinforcement member (12) is further provided between the third ceramic mica tape (11) and the outer sheath (13).
A method for preparing the all-dielectric fire-resistant optical cable according to any one of claims 1 to 9, characterized in that it comprises the following steps:

S1: Extruding the raw material of the inner layer casing and the raw material of the outer layer casing simultaneously outside the optical fiber and the water blocking material wrapping the optical fiber to form a unit cable;

S2: wrapping ceramic mica tape around the unit cable;

S3: twisting a number of unit cables wrapped with ceramic mica tape around a non-metallic central reinforcement to form a cable core;

S4: wrapping a water-blocking tape, a second ceramic mica tape and an insulating tape around the cable core in sequence to obtain a stable cable core structure;

S5: extruding an inner sheath outside the stable cable core structure;

S6: wrapping a ceramic mica tape around the inner sheath and placing a non-metallic auxiliary reinforcement member;

S7: Extruding a layer of outer sheath outside the non-metallic auxiliary reinforcement member to obtain the all-dielectric fire-resistant optical cable.