Preparation process of low-temperature-resistant and high-temperature-resistant flame-retardant cable

Abstract

The invention discloses a preparation process of a low-temperature-resistant and high-temperature-resistant flame-retardant cable. The cable sequentially comprises a conductor, an insulating layer, a belting layer and a sheath layer from inside to outside, the insulating layer is formed by taking hydrogenated nitrile rubber as a matrix and matching with a halogen-free flame retardant, a charring agent and a cross-linking agent; the belting layer is a ceramic silicone rubber-glass fiber cloth composite belt; and the sheath layer is formed by taking a thermoplastic polyurethane elastomer as a matrix and cooperating with an intumescent halogen-free flame retardant. The insulating layer is based on hydrogenated butadiene-acrylonitrile rubber and has a long-term use temperature range of-50 DEG C to 150 DEG C or above. And a high-temperature-resistant formula system is matched, so that the cable can work in an extreme temperature environment for a long time.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wire and cable manufacturing, in particular to a low-high temperature resistant flame-retardant cable preparation process. BACKGROUND

[0002] With the rapid development of new energy, aerospace, rail transportation, special equipment and other fields, the performance requirements of supporting cables are increasingly stringent. The polymer materials (such as PVC, ordinary polyolefins) of traditional cables are prone to soften and degrade at high temperatures, and become hard and brittle at low temperatures. Their flame retardancy also depends on halogen-containing flame retardants, which can produce a large amount of smoke and corrosive hydrogen halide gas during combustion, and cannot meet the safety requirements of the above-mentioned fields.

[0003] Currently, although there are special cables prepared from silicone rubber, fluoroplastic and other materials, they often have problems such as complex process, high cost, or insufficient performance in certain aspects (such as mechanical strength, oil resistance, flame retardant efficiency).

[0004] Therefore, it is of great practical significance to develop a low-high temperature resistant flame-retardant cable preparation technology with excellent comprehensive performance, feasible process and relatively controllable cost. SUMMARY

[0005] The technical problem solved by the present application is to provide a low-high temperature resistant flame-retardant cable preparation process.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a low-high temperature resistant flame-retardant cable, which comprises, from inside to outside, a conductor, an insulation layer, a wrapping layer and a sheath layer; the insulation layer is composed of hydrogenated nitrile rubber as a matrix, combined with halogen-free flame retardant, char-forming agent and crosslinking agent; the wrapping layer is a ceramicized silicone rubber-glass fiber cloth composite tape; the sheath layer is composed of thermoplastic polyurethane elastomer as a matrix, combined with intumescent halogen-free flame retardant.

[0007] Further, the halogen-free flame retardant of the insulation layer includes nano-sized surface-modified magnesium hydroxide and microencapsulated red phosphorus masterbatch.

[0008] Further, the intumescent halogen-free flame retardant of the sheath layer includes a compounded system of ammonium polyphosphate, melamine cyanurate and expandable graphite.

[0009] Another object of the present application is to provide a low-high temperature resistant flame-retardant cable process, comprising the following steps:

[0010] S1: conductor preparation;

[0011] S2: insulation layer extrusion: extruding the insulation material on the conductor through a warm water vulcanization or infrared vulcanization production line;

[0012] S3: wrapping the tape layer: wrapping the ceramicized silicone rubber-glass fiber cloth composite tape outside the insulated core;

[0013] S4: sheath layer extrusion: extruding the sheath material outside the tape layer through an extruder; S5: winding, inspection and packaging.

[0014] Further, in step S2, the extruder head temperature of the insulation layer extrusion is controlled at 85-95℃, and the vulcanization pipeline temperature is controlled at 200-220℃.

[0015] Further, in step S3, the wrapping overlap rate is not less than 25%.

[0016] Further, in step S4, the extruder temperature of the sheath layer extrusion is 160-195℃ from the feeding port to the head.

[0017] Compared with the prior art, the beneficial effects of the present application are:

[0018] 1. Excellent temperature resistance: the insulation layer uses hydrogenated nitrile rubber (HNBR) as the base, which itself has a long-term use temperature range of-50℃ to 150℃ or above. With the high-temperature resistant formula system, the cable can work in extreme temperature environment for a long time.

[0019] 2. High-efficiency environmental protection flame retardant: the synergistic flame retardant system (insulation layer) of "magnesium hydroxide + microcapsule red phosphorus" and the intumescent flame retardant system (sheath layer) of "APP + MCA + expandable graphite" are used to achieve halogen-free flame retardation. The amount of smoke generated during combustion is low, and there is no corrosive gas. The ceramicized silicone rubber composite tape wrapped outside can form a hard ceramic carbonized layer in the flame, effectively isolating the flame and oxygen, and realizing the fire resistance function.

[0020] 3. Excellent mechanical and environmental performance: TPU sheath provides excellent wear resistance, oil resistance and tear resistance. The overall structural design makes the cable have good flexibility and impact resistance.

[0021] 4. Mature and stable process: the extrusion and wrapping processes used are mature processes in the cable industry, easy to realize large-scale production, and stable quality control. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The figure is a schematic diagram of the cable structure in the present application. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of the present application.

[0024] The present application provides a technical solution:

[0025] In a first aspect, the present application provides a low-high temperature resistant flame-retardant cable, which comprises, from inside to outside, in order:

[0026] 1. Conductor: twisted with nickel-plated or tin-plated soft copper wire to improve the oxidation resistance and weldability of the conductor.

[0027] 2. Insulating layer: a high-temperature resistant polymer layer extruded on the conductor.

[0028] 3. Tape layer: an inorganic fire-resistant layer wrapped around the insulating core.

[0029] 4. Sheath layer: an outer protective layer extruded on the tape layer.

[0030] In a second aspect, the present application provides a preparation process of the above-mentioned cable, comprising the following steps:

[0031] S1: Conductor preparation: select a nickel-plated or tin-plated soft copper twisted conductor that meets the requirements, and prepare it through processes such as wire drawing, annealing, and twisting to ensure that the conductor surface is smooth, non-oxidized, and structurally stable.

[0032] S2: Insulating layer extrusion: use an extrusion mold to extrude a high-temperature resistant insulating material on the conductor.

[0033] Insulating material formula (weight parts):

[0034] Hydrogenated nitrile rubber (HNBR): 100 parts;

[0035] Magnesium hydroxide flame retardant (nanoscale, surface modified): 60-80 parts;

[0036] Red phosphorus masterbatch (microencapsulated): 5-10 parts;

[0037] Diatomite: 10-20 parts;

[0038] Platinum-gold catalyst system: 1-2 parts;

[0039] Co-crosslinking agent (triallyl isocyanurate, TAIC): 2-3 parts;

[0040] Other additives (including antioxidants, structure control agents, etc.): 3-5 parts;

[0041] Process parameters:

[0042] Extruder temperature: Zone 1 60-70℃, Zone 2 70-80℃, Die 85-95℃;

[0043] Vulcanization pipeline temperature: 200-220℃;

[0044] Production line speed: 20-30m / min;

[0045] Crosslinking and curing by dry method or infrared vulcanization.

[0046] S3: Tape layer winding: After cabling, a layer or more of ceramicized silicone rubber-glass fiber cloth composite tape is wound on the outside of the insulated core.

[0047] Composite tape structure: Alkali-free glass fiber cloth as base material, double-sided coated with ceramicized silicone rubber coating.

[0048] Winding parameters: Overlapping rate not less than 25%, uniform and stable winding tension.

[0049] S4: Sheath layer extrusion: Extruding an outer sheath outside the tape layer.

[0050] Sheath material formula (parts by weight):

[0051] Thermoplastic polyurethane elastomer (TPU, polyester type): 100 parts;

[0052] Ammonium polyphosphate (APP): 15-25 parts;

[0053] Melamine cyanurate (MCA): 10-15 parts;

[0054] Expandable graphite: 5-10 parts;

[0055] Lubricant: 0.5-1 part;

[0056] Anti-UV agent: 0.5-1 part;

[0057] Process parameters:

[0058] Extruder temperature: Zone 1 160-170℃, Zone 2 170-180℃, Zone 3 180-190℃, Die 185-195℃;

[0059] Cooling method: Warm water step cooling.

[0060] S5: Winding, inspection and packaging: The finished cable is wound, various performance tests (such as conduction, voltage resistance, insulation resistance, flame retardant test, etc.) are carried out according to the standard, and after passing the test, it is packaged and stored in the warehouse.

[0061] A low high temperature resistant flame-retardant cable with a conductor nominal cross-section of 2.5mm 2 is prepared.

[0062] 1. Conductor: Tinned copper wire is used for twisting.

[0063] 2. Insulation layer: The insulation layer is extruded according to the formula (taking the intermediate value) and process of the above S2 step, and the thickness is 0.7mm.

[0064] 3. Tape layer: A ceramicized silicone rubber-glass fiber cloth composite tape with a thickness of 0.2mm is wrapped, and the overlap rate is 30%.

[0065] 4. Sheath layer: The sheath is extruded according to the formula (taking the intermediate value) and process of the above S4 step, and the thickness is 1.2mm.

[0066] 5. Test: The finished cable passes the flame-retardant, fire-resistant, high and low temperature cycle tests specified in GB / T 19666, IEC 60331 and other standards, and has excellent performance.

[0067] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements and changes can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A flame-retardant cable resistant to low and high temperatures, characterized in that: From the inside out, it includes a conductor (1), an insulation layer (2), a wrapping layer (3), and a sheath layer (4); the insulation layer (2) is composed of hydrogenated nitrile rubber as the matrix, combined with halogen-free flame retardant, charring agent and crosslinking agent; the wrapping layer (3) is a ceramicized silicone rubber-glass fiber cloth composite tape; the sheath layer (4) is composed of thermoplastic polyurethane elastomer as the matrix, combined with intumescent halogen-free flame retardant.

2. The low-temperature and high-temperature resistant flame-retardant cable according to claim 1, characterized in that: The halogen-free flame retardant of the insulating layer (2) includes nanoscale surface-modified magnesium hydroxide and microencapsulated red phosphorus masterbatch.

3. The low-temperature and high-temperature resistant flame-retardant cable according to claim 1, characterized in that: The intumescent halogen-free flame retardant of the sheath layer (4) includes a compound system of ammonium polyphosphate, melamine cyanurate and expandable graphite.

4. A process for preparing a low-temperature and high-temperature resistant flame-retardant cable as described in any one of claims 1-3, characterized in that: Includes the following steps: S1: Conductor preparation; S2: Insulation layer extrusion: The insulating material is extruded onto the conductor through a warm water vulcanization or infrared vulcanization production line; S3: Wrapping with a layer of ceramicized silicone rubber-glass fiber cloth composite tape is wrapped around the outside of the insulated wire core; S4: Sheath layer extrusion: The sheath material is extruded onto the outside of the tape layer using an extruder; S5: Winding, inspection and packaging.

5. The manufacturing process of the low-temperature and high-temperature resistant flame-retardant cable according to claim 4, characterized in that: In step S2, the extruder head temperature for extruding the insulation layer is controlled at 85-95℃, and the vulcanization pipe temperature is controlled at 200-220℃.

6. The manufacturing process of the low-temperature and high-temperature resistant flame-retardant cable according to claim 4, characterized in that: In step S3, the wrapping overlap rate is not less than 25%.

7. The manufacturing process of the low-temperature and high-temperature resistant flame-retardant cable according to claim 4, characterized in that: In step S4, the extruder temperature for extruding the sheath layer is 160-195℃ from the feed port to the die head.

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