Fireproof flame-retardant network twisted pair and its production process
By optimizing the arrangement of the twisted pair cores and transmission cores, and combining multiple shielding and filling layers, the problems of low space utilization and high manufacturing cost in composite cables are solved, achieving efficient electromagnetic shielding and fire-retardant effects.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI HUIHAI INFORMATION TECH CO LTD
- Filing Date
- 2026-06-23
- Publication Date
- 2026-07-31
AI Technical Summary
The spatial arrangement of signal cables and power cables in existing composite cables is unreasonable, resulting in low cross-sectional utilization. The shielding structure of the signal cables is complex, the manufacturing cost is high, and there is a lack of fire-resistant and flame-retardant design.
It adopts a twisted pair core design, including at least two sets of twisted pairs, with a first shielding layer on the outside, and the power transmission cores are arranged along the length direction. It forms a circular or elliptical structure through a filling layer and a sheath layer, and uses conductive or semi-conductive filling materials and multiple shielding layers for electromagnetic shielding and protection.
It improves the space utilization of cables, reduces production costs, and achieves efficient electromagnetic shielding and fire-retardant effects.
Smart Images
Figure CN122494360A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of cable technology, specifically to a fire-resistant and flame-retardant twisted-pair network cable and its manufacturing process. Background Technology
[0002] With the continuous development of applications such as smart buildings, the Internet of Things, and remote power supply equipment, terminal devices often require both DC power supply and network signal access. For example, Chinese invention patent CN105788746B discloses a hybrid cable for electromagnetic interference protection, which integrates power cables and communication cables. By setting a magnetic shielding layer for the power cable to eliminate its external magnetic field and setting a composite shielding layer for the signal cable to resist external interference, electromagnetic compatibility between high-voltage and low-voltage systems under the condition of close parallel wiring is achieved.
[0003] The simple parallel combination of signal cables and power cables lacks optimized spatial arrangement design for signal cable groups, resulting in low utilization of cable cross-sectional space. Furthermore, the shielding structure of signal cables is relatively complex, requiring multiple layers of shielding for each cable, leading to higher manufacturing costs. In addition, the fire-resistant and flame-retardant design of the cables is of great significance in locations with high fire safety requirements. Summary of the Invention
[0004] To address the shortcomings of existing technologies, this invention provides a fire-resistant and flame-retardant network twisted-pair cable and its manufacturing process, solving the problems of low cross-sectional utilization due to unreasonable spatial arrangement of signal cables and power cables, high manufacturing costs due to complex shielding structures of signal cables, and the lack of overall fire-resistant and flame-retardant design in existing composite cables.
[0005] To achieve the above objectives, the present invention provides the following technical solution: A fire-resistant and flame-retardant twisted-pair network cable includes: A twisted-pair core, which includes at least two sets of twisted-pair wires; a first shielding layer is provided on the outside of the twisted-pair core, and the cross-sectional shape of the twisted-pair core is rectangular, with the first shielding layer covering the outside of the twisted-pair core. A power transmission core extending along the length of the twisted pair core, wherein two sets of the power transmission core are provided and distributed on both sides of the long twisted pair core; A filler layer is provided on the outside of the twisted pair core and the transmission core, and the overall cross-section of the twisted pair core, the transmission core and the filler layer is circular or elliptical. A sheath layer is provided on the outside of the filler layer.
[0006] Preferably, the twisted pair is formed by twisting two first conductors with insulating protective layers together, and at least two sets of the twisted pair are linearly spaced and coated with a shaping resin to form an integral structure. An embedding groove is provided on the outer side of the shaping resin layer, and a sheet shield is provided inside the embedding groove.
[0007] Preferably, the twisted pair group is an even group, and the two groups of transmission cores are symmetrically distributed on both sides of the twisted pair core.
[0008] Preferably, the sheath layer comprises, from the inside out: a mica flame-retardant layer, an inner sheath layer, and an outer sheath layer; The inner sheath is a low-smoke, halogen-free, flame-retardant polyolefin; the outer sheath is a cross-linked polyethylene insulation layer.
[0009] Preferably, the filler layer is a conductive filler layer or a semi-conductive filler layer, which is composed of a matrix resin and conductive fillers dispersed in the matrix resin.
[0010] Preferably, the first shielding layer includes an inner shielding layer and an outer shielding layer arranged sequentially from the inside to the outside, wherein the inner shielding layer is an aluminum foil longitudinally wrapped shielding layer and the outer shielding layer is a copper foil wrapped shielding layer.
[0011] Preferably, the cross-section of the twisted pair core is oblong, and its two ends in the width direction are connected to the upper and lower straight edges in the thickness direction by an arc transition.
[0012] Preferably, the sheet shielding component is a metal foil sheet or a semi-conductive sheet.
[0013] Preferably, the cross-section of the sheet shield is wavy or zigzag.
[0014] A manufacturing process for fire-resistant and flame-retardant twisted-pair network cables, specifically comprising the following steps: S1. Arrange at least two sets of twisted pairs in a linear pattern along the width direction. Use an extruder to fill the gaps between the arranged twisted pairs with molding resin. After curing, a twisted pair core with a rectangular cross-section is formed. At the same time, an embedding groove is formed on the outside of the molding resin through an extrusion die. S2. The sheet shielding component is continuously embedded into the embedding groove and pressed using upper and lower guide rollers; S3. A longitudinal wrapping device is used to wrap aluminum foil around the outer periphery of the twisted pair core to form an inner shielding layer; then a spiral wrapping device is used to wrap copper foil around the outside of the inner shielding layer to form an outer shielding layer. S4. Power transmission cores are arranged on both sides of the twisted pair core width direction, and each power transmission core extends along the length direction of the twisted pair core. S5. Using an extruder, conductive or semi-conductive filler material is extruded onto the outside of the twisted pair core, the first shielding layer, and the transmission core, filling the gaps between the components and making the overall cross-section of the twisted pair core, the transmission core, and the filler layer circular or elliptical. S6. Using a wrapping machine, wrap two or more layers of mica tape on the outside of the filler layer in an overlapping manner to form a mica flame-retardant layer; the overlap rate of the mica tape is not less than 30%, and the wrapping angle is controlled between 40° and 50°. S7. Using an extruder, a low-smoke halogen-free flame-retardant polyolefin material is extruded onto the outside of the mica flame-retardant layer to form an inner protective layer. S8. Using an extruder, cross-linked polyethylene material is extruded onto the outside of the inner protective layer to form an outer protective layer.
[0015] This invention provides a fire-resistant and flame-retardant twisted-pair network cable and its manufacturing process. It offers the following advantages: 1. In this invention, at least two sets of twisted-pair wires are designed to be linearly distributed, so that the cross-sectional shape of the core of the twisted-pair wires is rectangular. In this way, multiple sets of twisted-pair wires can be concentrated together to form a signal shielding structure in conjunction with a first shielding layer that covers multiple sets of twisted-pair wires. Compared with designing a signal shielding structure for each set of twisted-pair wires, the production and manufacturing cost is lower.
[0016] 2. In this invention, two sets of power transmission cores are distributed on both sides of the long twisted pair core, and the distribution of the twisted pair core and the two sets of power transmission cores is stabilized by the filling layer. The spatial distribution structure formed in this way has a high utilization rate of cable cross-section space, and the cable diameter is smaller under the same design requirements of power transmission cores and twisted pair groups. Attached Figure Description
[0017] Figure 1 This is a perspective view of a fire-resistant and flame-retardant twisted-pair network cable proposed in this invention. Figure 2 This is a cross-sectional view of a fire-resistant and flame-retardant twisted-pair network cable proposed in this invention. Figure 3 This is a perspective view of the core of a fire-resistant and flame-retardant network twisted-pair cable proposed in this invention.
[0018] Among them, 1. Twisted pair core; 2. Transmission core; 3. Filler layer; 4. Sheath layer; 5. First shielding layer; 101. First conductor; 102. Shaping resin layer; 103. Embedded groove; 104. Sheet shield; 401. Mica flame retardant layer; 402. Inner sheath; 403. Outer sheath. Detailed Implementation
[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0020] Example 1: like Figures 1-3 As shown, this embodiment of the invention provides a fire-resistant and flame-retardant twisted-pair network cable for simultaneously realizing DC power transmission and network signal transmission. It is suitable for application scenarios that require composite wiring of strong and weak current, such as smart buildings, IoT terminal devices, and remote power supply equipment. Specifically, it includes: twisted-pair core 1, first shielding layer 5, power transmission core 2, filling layer 3, and sheath layer 4.
[0021] The twisted pair core 1 includes at least two sets of twisted pair wires, for example, four sets (a total of eight first conductors 101, forming two sets of twisted pair wires). A first shielding layer 5 is provided on the outside of the twisted pair core 1. The first shielding layer 5 provides electromagnetic shielding for the twisted pair core 1 containing multiple sets of twisted pair wires. Its main function is to reduce the interference caused by the power transmission core 2 to the twisted pair wires of the twisted pair core 1.
[0022] In this method, the first shielding layer 5 is used to shield all twisted pair groups. Compared with the traditional distributed design of signal wires, the structure of this method is simpler and the manufacturing cost is lower.
[0023] The cross-sectional shape of the twisted pair core 1 is designed to be rectangular, and the first shielding layer 5 covers the outside of the twisted pair core 1. The interference between the linearly arranged twisted pair groups is small. The first shielding layer 5 is in the form of a cover, which can protect the twisted pair groups inside relatively completely. The transmission core 2 extends along the length of the twisted pair core 1, and there are two sets of transmission core 2 (corresponding to the positive / negative poles of the DC transmission line), which are distributed on both sides of the long twisted pair core 1. This arrangement of the twisted pair core 1 and the two sets of transmission core 2 can greatly reduce the space occupied. The diameter of the twisted pair cable in the fire-retardant network is relatively small. A filler layer 3 is provided on the outside of the twisted pair core 1 and the transmission core 2, and the overall cross-section of the twisted pair core 1, the transmission core 2 and the filler layer 3 is circular or elliptical. The filler layer 3 is used to stabilize the distribution of the twisted pair core 1 and the two sets of transmission cores 2. The filler layer 3 also provides flexible protection for the twisted pair core 1 and the two sets of transmission cores 2 (the filler layer 3 can disperse external mechanical destructive forces). A sheath layer 4 is provided on the outside of the filler layer 3, which serves as insulation and protection.
[0024] It is understandable that designing at least two sets of twisted-pair cables in a linear distribution results in a rectangular cross-sectional shape for the resulting twisted-pair core 1. This allows for the concentration of multiple twisted-pair cables, which, together with the first shielding layer 5 enclosing them, form a signal shielding structure. Compared to designing a signal shielding structure for each individual twisted-pair cable, this approach results in lower production and manufacturing costs. Distributing two sets of transmission cores 2 on both sides of the rectangular twisted-pair core 1, and using a filler layer 3 to stabilize the distribution of the twisted-pair core 1 and the two sets of transmission cores 2, results in a higher utilization rate of the cable cross-sectional space in this spatial distribution structure. Under the same design requirements for transmission cores 2 and twisted-pair cables, the resulting cable diameter is smaller.
[0025] In one embodiment, the twisted pair is formed by twisting two first conductors 101 with insulating protective layers together. The first conductors of the twisted pair are twisted in a counterclockwise direction (i.e., S-direction) with a twist pitch of 12 mm-25 mm. The twisted pair can ensure that the transmitted weak signal is not drowned out (common mode signal cancellation, differential amplification technology), thereby ensuring communication quality. At least two twisted pair groups are linearly spaced, and the twisting directions of adjacent twisted pair groups are opposite, which can further reduce inter-group crosstalk. At least two twisted pair groups are coated with a shaping resin to form an integral structure, that is, a shaping resin layer 102 is formed on the outside of at least two twisted pair groups. An embedding groove 103 is opened on the outside of the shaping resin layer 102. A sheet shield 104 is provided inside the embedding groove 103. The sheet shield 104 forms electromagnetic shielding on its surface. It works in conjunction with the first shielding layer 5 to reduce the electromagnetic interference of the power transmission core 2 to the twisted pair group.
[0026] Understandably, the first shielding layer 5 covers the outer periphery of the twisted pair core 1, providing overall electromagnetic shielding protection for all twisted pair groups within the twisted pair core 1; while the sheet shielding component 104 is embedded in the embedding groove 103 inside the twisted pair core 1, forming internal local electromagnetic shielding between twisted pair groups and between the twisted pair groups and the power transmission core 2. Through the combination of the sheet shielding component 104 and the first shielding layer 5, a double shielding barrier is constructed between the power transmission core 2 and the twisted pair groups—externally, the first shielding layer 5 completely wraps around the twisted pair core 1, and internally, the sheet shielding component 104 forms a local partition within the molding resin layer 102, thereby effectively suppressing the interference of the electromagnetic field generated by the power transmission core 2 on the weak signals transmitted in the twisted pair groups. In addition, the shaping resin layer 102 fixes each twisted pair group into one piece, ensuring the stability of the relative positions between each twisted pair group and between the twisted pair group and the sheet shield 104 in the direction of cable length, and preventing the relative displacement of each component when the cable is bent or subjected to external force, which would affect the shielding effect.
[0027] In one embodiment, the twisted pair groups are even numbers, such as 4, 6, or 8 groups, with the two groups of transmission cores 2 symmetrically distributed on both sides of the twisted pair core 1.
[0028] It is understandable that designing the twisted pair groups as even-numbered groups, with the center of the fire-resistant and flame-retardant network twisted pair corresponding to the interval area between two adjacent twisted pair groups located in the middle position; symmetrically distributing the two sets of transmission cores 2 on both sides of the twisted pair core 1, with the line connecting the centers of the two sets of transmission cores 2 perpendicularly bisecting these twisted pair groups, and the position of the transmission core 2 closest to the center having a suitable distance from the twisted pair group; this method can further optimize the spatial distribution of each twisted pair group and the two sets of transmission cores 2.
[0029] In one embodiment, the sheath layer 4 comprises, from the inside out, a mica flame-retardant layer 401, an inner sheath layer 402, and an outer sheath layer 403. The mica flame-retardant layer 401 serves as a flame-retardant layer and a transition filler layer 3, while the inner sheath layer 402 and the outer sheath layer 403 both serve as insulation and protection.
[0030] The inner sheath 402 is a low-smoke, halogen-free flame-retardant polyolefin, a material with stable flame-retardant effect. Combined with the mica flame-retardant layer 401 and the filler layer 3, it can achieve excellent flame-retardant effect. The outer sheath 403 is a cross-linked polyethylene insulation layer, which is an insulation and sealing protection layer.
[0031] In one embodiment, the filler layer 3 is a conductive filler layer or a semi-conductive filler layer, which is composed of a matrix resin and conductive fillers dispersed in the matrix resin.
[0032] The filling layer 3 is formed by filling with conductive or semi-conductive filling material. On the one hand, it can define the position of the twisted pair core 1 and the two sets of transmission cores 2; on the other hand, it can also play a certain role in electromagnetic shielding.
[0033] In one embodiment, the first shielding layer 5 includes an inner shielding layer and an outer shielding layer arranged sequentially from the inside to the outside. The inner shielding layer is an aluminum foil longitudinally wrapped shielding layer, and the outer shielding layer is a copper foil wrapped shielding layer. The double-layer structure formed by the inner shielding layer and the outer shielding layer can achieve a better shielding effect.
[0034] In one embodiment, the cross-section of the twisted pair core 1 is oblong, and its two ends in the width direction are connected by an arc transition to the upper and lower straight edges in the thickness direction. The design of the oblong side can adapt to the filling layer 3 with a circular cross-section on the outer contour, so that the filling layer 3 can better wrap the twisted pair core 1 and the two sets of transmission cores 2.
[0035] In one embodiment, the sheet shield 104 is a metal foil sheet or a semi-conductive sheet, and the sheet shield 104 has the function of electromagnetic shielding.
[0036] Preferably, the cross-section of the sheet shield 104 is wavy or zigzag. Compared with a flat sheet, the wavy or zigzag sheet has a larger surface area under the same embedding groove width, which can cover a wider electromagnetic shielding area. At the same time, its crests or bends form multiple points of contact with the inner wall of the embedding groove 103, which not only enhances the positioning stability of the sheet shield 104 in the embedding groove 103 and prevents displacement or overturning when the cable is bent or subjected to external force, but also further improves the continuity of electromagnetic shielding through multi-point contact.
[0037] Example 2: like Figures 1-3 As shown, this embodiment of the invention provides a manufacturing process for fire-retardant twisted-pair network cables, used to produce the fire-retardant twisted-pair network cables in Embodiment 1, specifically including the following steps: S1. Prepare multiple sets of pre-wound twisted pair wires and arrange them in a straight line along the width direction. Use an extruder to fill the gaps between the arranged twisted pair wires with molding resin. After curing, a rectangular cross-section twisted pair core 1 is formed. At the same time, an embedding groove 103 is formed on the outside of the molding resin through an extrusion die. That is, a protrusion corresponding to the embedding groove 103 is provided on the extrusion die, and the embedding groove 103 is formed directly during the process.
[0038] S2. The sheet shield 104 is continuously embedded into the embedding groove 103 and squeezed by the upper and lower guide wheels. The sheet shield 104 is embedded into the embedding groove 103 and then guided by the upper and lower guide wheel structure. During the guiding process, both are squeezed at the same time so that the sheet shield 104 is completely embedded into the embedding groove 103.
[0039] S3. A longitudinal wrapping device is used to wrap aluminum foil around the outer periphery of the twisted pair core 1 to form an inner shielding layer; then a wrapping device is used to spirally wrap copper foil around the outside of the inner shielding layer to form an outer shielding layer.
[0040] The inner and outer shielding layers form a double-layer shield, which provides better shielding performance.
[0041] S4. Power transmission cores 2 are arranged on both sides of the twisted pair core 1 in the width direction, and each power transmission core 2 extends along the length direction of the twisted pair core 1.
[0042] S5. Then, using an extruder, conductive or semi-conductive filler material is extruded onto the outside of the twisted pair core 1, the first shielding layer 5, and the power transmission core 2, filling the gaps between the components and making the overall cross-section of the twisted pair core 1, the power transmission core 2, and the filler layer 3 circular or elliptical.
[0043] S6. Using a wrapping machine, wrap two or more layers of mica tape around the outside of the filling layer 3 in an overlapping manner to form a mica flame-retardant layer 401; the overlap rate of the mica tape is not less than 30%, and the wrapping angle is controlled between 40° and 50°.
[0044] S7. Using an extruder, a low-smoke halogen-free flame-retardant polyolefin material is extruded onto the outside of the mica flame-retardant layer 401 to form the inner protective layer 402. S8. Then, using an extruder, cross-linked polyethylene material is extruded onto the outside of the inner sheath 402 to form the outer sheath 403. Finally, after cooling, a fire-retardant twisted-pair cable is obtained.
[0045] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A fire-resistant and flame-retardant twisted-pair network cable, characterized in that, include: Twisted pair core (1), which includes at least two sets of twisted pairs; The outside of the twisted pair core (1) is provided with a first shielding layer (5). The cross-sectional shape of the twisted pair core (1) is rectangular, and the first shielding layer (5) covers the outside of the twisted pair core (1). A power transmission core (2) extends along the length direction of the twisted pair core (1), and the power transmission core (2) is provided in two sets and distributed on both sides of the long twisted pair core (1); A filling layer (3) is provided on the outside of the twisted pair core (1) and the power transmission core (2), and the overall cross-section of the twisted pair core (1), the power transmission core (2) and the filling layer (3) is circular or elliptical. A sheath layer (4) is provided on the outside of the filling layer (3).
2. The fire-resistant and flame-retardant twisted-pair network cable according to claim 1, characterized in that: The twisted pair is formed by twisting two first conductors (101) with insulating protective layers together. At least two sets of the twisted pair are linearly spaced and are coated with a shaping resin to form an integral structure. An embedding groove (103) is provided on the outer side of the shaping resin layer (102), and a sheet shield (104) is provided inside the embedding groove (103).
3. The fire-resistant and flame-retardant twisted-pair network cable according to claim 2, characterized in that: The twisted pair is an even number of pairs, with the two sets of power transmission cores (2) symmetrically distributed on both sides of the twisted pair core (1).
4. The fire-resistant and flame-retardant twisted-pair network cable according to claim 1, characterized in that: The sheath layer (4) includes, from the inside to the outside, a mica flame retardant layer (401), an inner sheath layer (402), and an outer sheath layer (403). The inner sheath (402) is a low-smoke, halogen-free, flame-retardant polyolefin; the outer sheath (403) is a cross-linked polyethylene insulation layer.
5. A fire-resistant and flame-retardant twisted-pair network cable according to claim 1, characterized in that: The filler layer (3) is a conductive filler layer or a semi-conductive filler layer, which is composed of a matrix resin and conductive fillers dispersed in the matrix resin.
6. A fire-resistant and flame-retardant twisted-pair network cable according to claim 1, characterized in that: The first shielding layer (5) includes an inner shielding layer and an outer shielding layer arranged sequentially from the inside to the outside. The inner shielding layer is an aluminum foil longitudinally wrapped shielding layer, and the outer shielding layer is a copper foil wrapped shielding layer.
7. A fire-resistant and flame-retardant twisted-pair network cable according to claim 1, characterized in that: The cross-section of the twisted pair core (1) is oblong, and its two ends in the width direction are connected by an arc transition to the upper and lower straight edges in the thickness direction.
8. A fire-resistant and flame-retardant twisted-pair network cable according to claim 2, characterized in that: The sheet shielding component (104) is a metal foil sheet or a semi-conductive sheet.
9. A fire-resistant and flame-retardant twisted-pair network cable according to claim 8, characterized in that: The cross-section of the sheet shield (104) is wavy or zigzag.
10. A manufacturing process for fire-resistant and flame-retardant twisted-pair network cables, characterized in that: The method for producing the fire-resistant and flame-retardant twisted-pair network cable according to any one of claims 1-9 specifically includes the following steps: S1. Arrange at least two sets of twisted pairs in a straight line along the width direction. Use an extruder to fill the gaps between the arranged twisted pairs with molding resin. After curing, a twisted pair core with a rectangular cross-section is formed (1). At the same time, an embedding groove (103) is formed on the outside of the molding resin through an extrusion die. S2. The sheet shield (104) is continuously embedded into the embedding groove (103) and squeezed using upper and lower guide rollers; S3. A longitudinal wrapping device is used to wrap aluminum foil around the outer periphery of the twisted pair core (1) to form an inner shielding layer; then a wrapping device is used to spirally wrap copper foil around the outside of the inner shielding layer to form an outer shielding layer. S4. Power transmission cores (2) are arranged on both sides of the width direction of the twisted pair core (1), and each power transmission core (2) extends along the length direction of the twisted pair core (1). S5. Using an extruder, conductive or semi-conductive filler material is extruded onto the outside of the twisted pair core (1), the first shielding layer (5), and the power transmission core (2) to fill the gaps between the components and make the overall cross-section of the twisted pair core (1), the power transmission core (2), and the filler layer (3) circular or elliptical. S6. Using a wrapping machine, wrap two or more layers of mica tape on the outside of the filling layer (3) in an overlapping wrapping manner to form a mica flame-retardant layer (401); the overlap rate of the mica tape is not less than 30%, and the wrapping angle is controlled between 40° and 50°. S7. Using an extruder, a low-smoke halogen-free flame-retardant polyolefin material is extruded onto the outside of the mica flame-retardant layer (401) to form an inner protective layer (402). S8. Using an extruder, cross-linked polyethylene material is extruded onto the outside of the inner protective layer (402) to form an outer protective layer (403).