Low-smoke halogen-free high-flame-retardant power cable

Abstract

The invention relates to the technical field of electric wires and cables, and discloses a low-smoke halogen-free high-flame-retardant power cable which comprises a cable conductor, a conductor insulating layer, an inner protective layer, an in-situ reaction authigenic ceramic composite layer and an outer sheath from inside to outside, and the in-situ reaction authigenic ceramic composite layer is a core. The ceramic material can be converted into a hard ceramic structural body with high strength and high heat insulation performance in situ at high temperature in a fire disaster. By adopting the technical scheme, the physical and mechanical properties of the cable can be improved, the flame impact can be effectively resisted, the line integrity in a fire can be greatly improved, and the low-smoke halogen-free environment-friendly characteristics can be realized.

Description

Technical Field

[0001] This invention belongs to the field of wire and cable technology, and specifically relates to a low-smoke, halogen-free, high flame-retardant power cable. Background Technology

[0002] As the core of modern energy transmission and distribution systems, power cables are the cornerstone of ensuring the safe, stable, and reliable operation of national economic development, industrial production, and the normal functioning of society. Against the backdrop of accelerating urbanization and increasingly dense infrastructure, the application scenarios for cables are becoming more complex and concentrated, especially in densely populated or critical facilities such as high-rise buildings, underground spaces, transportation hubs, and data centers. The fire safety of cable systems has been elevated to an unprecedented strategic level. In fire accidents, cables are not only potential ignition sources but can also become channels for the spread of flames and toxic fumes. Therefore, the development of power cables that combine environmental friendliness with superior fire resistance has become an important direction for continuous exploration in the field of cable technology.

[0003] To address the serious safety hazards posed by the release of large amounts of toxic and corrosive gases and dense smoke during combustion of traditional halogen-containing cables such as PVC, those skilled in the art have developed low-smoke halogen-free cables. This technological solution was a milestone at the time. Its core principle lies in using halogen-free polymer materials such as polyolefins as the matrix resin, and compounding it with a large amount of inorganic hydroxide flame retardants, such as aluminum hydroxide or magnesium hydroxide. Specifically, when the cable encounters flames or high temperatures, these hydroxide flame retardants undergo an endothermic decomposition reaction, releasing water of crystallization.

[0004] This process produces flame-retardant effects at both the physical and chemical levels: on the one hand, the decomposition reaction absorbs a large amount of heat, effectively reducing the surface temperature of the polymer material and slowing down its pyrolysis process; on the other hand, the released water vapor can dilute the oxygen concentration in the air and the concentration of flammable gases released by the pyrolysis of the polymer material, thus playing a role in suffocation and fire extinguishing. Finally, the metal oxide residues generated after decomposition can also form a carbonized or ceramicized layer on the material surface, isolating oxygen and heat transfer. This technology path based on material modification successfully solves the problem of secondary disasters caused by traditional cables in fires, significantly improves visibility at fire scenes and the safety of personnel escape, and constitutes the mainstream technical form of current environmentally friendly and safe cables.

[0005] However, with the continuous development of related technologies and the increasingly stringent performance requirements of application scenarios, the inherent characteristics of the aforementioned low-smoke halogen-free flame-retardant technology based on highly filled inorganic hydroxides at the core are gradually revealing its inherent technical contradictions and performance bottlenecks when facing higher levels of flame retardancy requirements. The reason for this is that the flame-retardant performance of this technology is strongly positively correlated with the amount of flame retardant added. To achieve a high flame-retardant rating, the filling amount of inorganic hydroxide flame retardant in the polymer matrix usually needs to reach an extremely high proportion, sometimes even exceeding 60% of the total mass. Such a high proportion of inorganic powder filling inevitably severely disrupts the original chain structure continuity of the polymer material, leading to a significant deterioration in the physical and mechanical properties of the composite material.

[0006] Specifically, this manifests as a significant decrease in the tensile strength and elongation at break of the cable insulation and sheath, resulting in increased brittleness and insufficient flexibility. This not only complicates cable production, laying, and installation but also makes the cable more susceptible to micro-cracks caused by bending, stretching, and other external forces, posing potential safety hazards for future operation. Furthermore, this method of relying solely on the material's inherent flame retardancy limits the quality of the resulting char layer. Under continuous and intense flame impact, the char layer composed of highly filled powder often exhibits a loose structure and insufficient mechanical strength, making it prone to cracking and detachment. It fails to form a durable and dense physical barrier, allowing the flame to penetrate and ignite unburned materials within, causing the flame to spread rapidly along the cable line.

[0007] This essentially reveals a deep-seated contradiction: the high-filling strategy adopted to improve flame retardancy sacrifices the mechanical integrity and char quality necessary for the material as a cable structural component. As a result, although the cable can meet the requirements of low smoke and halogen-free in real fire scenarios, it is difficult to achieve true high flame retardancy and line integrity, and it cannot effectively guarantee the continuous power supply capability of critical circuits during a fire.

[0008] Therefore, how to break through the performance ceiling of existing low-smoke halogen-free material systems, get rid of the single dependence on high-filler flame retardants, and achieve a synergistic improvement in flame retardant performance and material physical and mechanical properties through a new technical paradigm, while ensuring excellent environmental protection characteristics, and building a solid and stable fire barrier under fire conditions to prevent the spread of flames and ensure the continuous and stable power transmission, has become a key challenge and an urgent technical problem to be solved by those skilled in the art. Summary of the Invention

[0009] The purpose of this invention is to overcome the aforementioned deficiencies of the prior art and provide a low-smoke halogen-free, high flame-retardant power cable. This cable aims to resolve the technical contradiction of traditional low-smoke halogen-free cables, which excessively fill with inorganic flame retardants to achieve high flame-retardant ratings, leading to severe degradation of the material's physical and mechanical properties and insufficient protective capacity of the resulting char layer after combustion. This invention constructs a multi-level, functionally synergistic composite fire-resistant structure system, particularly by introducing a special functional layer that can undergo an in-situ reaction at high temperatures, transforming into a dense, high-strength ceramicized insulation body. This achieves superior flame-retardant and heat-insulating performance and maintain line integrity under fire conditions without sacrificing the material's basic physical and mechanical properties.

[0010] To achieve the above-mentioned objectives, the present invention provides a low-smoke halogen-free high flame-retardant power cable, which, from the inside out, includes at least one cable conductor, a conductor insulation layer covering the outer periphery of the cable conductor, an inner sheath disposed outside the conductor insulation layer, and an outer sheath covering the outermost part of the inner sheath. An in-situ reactive self-generated ceramic composite layer is also disposed between the inner sheath and the outer sheath. The in-situ reactive self-generated ceramicized composite layer is a composite material layer of a hard ceramicized structure.

[0011] Preferably, the material of the in-situ reaction self-generated ceramic composite layer is a ceramicizable organosilicon composite material, and the components of the ceramicizable organosilicon composite material include: organosilicon rubber matrix, low melting point glass powder, inorganic filler, and synergistic ceramicization and expansion foaming system.

[0012] Preferably, the components of the ceramizable organosilicon composite material specifically include: The silicone rubber matrix is ​​methyl vinyl silicone rubber; The low-melting-point glass powder is a borosilicate glass powder; The inorganic filler includes surface-modified wollastonite whiskers or mica powder; The synergistic ceramic formation and expansion foaming system is composed of microencapsulated ammonium polyphosphate, pentaerythritol and melamine; The ceramicizable organosilicon composite material also includes a ceramic-forming accelerator, which includes one of nano-titanium dioxide and ferric oxide.

[0013] Preferably, the components of the ceramicizable organosilicon composite material include, by mass parts: 100 parts methyl vinyl silicone rubber; 40-60 parts low melting point glass powder; 40-60 parts inorganic filler; 20-35 parts synergistic ceramicization and expansion foaming system; and 5-10 parts ceramicization accelerator.

[0014] Preferably, the vinyl molar fraction of the methyl vinyl silicone rubber is 0.15% to 0.25%; The softening point temperature of the low melting point glass powder is 680~750℃, and the particle size D90 is less than 15μm. The aspect ratio of the wollastonite whiskers is greater than 15:1; In the synergistic ceramic forming and expansion foaming system, the mass ratio of ammonium polyphosphate, pentaerythritol and melamine is 4:1:1. The degree of polymerization of the ammonium polyphosphate is greater than 1000, and it is surface microencapsulated using melamine-formaldehyde resin.

[0015] Preferably, the material of the conductor insulation layer is a low-smoke halogen-free flame-retardant polyolefin composite modified by irradiation crosslinking. The components of the low-smoke halogen-free flame-retardant polyolefin composite include: matrix resin, activated magnesium hydroxide, zinc borate, composite antioxidant system and crosslinking aid.

[0016] Preferably, the components of the conductor insulation layer material, by mass parts, include: 100 parts of matrix resin, wherein the blend of ethylene-vinyl acetate copolymer and ethylene-octene copolymer is composed of ethylene-vinyl acetate copolymer and ethylene-octene copolymer in a mass ratio of (70-80):(30-20), and the mass content of vinyl acetate in the ethylene-vinyl acetate copolymer is 25%~33%; 120~150 parts of active magnesium hydroxide, wherein the active magnesium hydroxide is surface activated by an aminosilane coupling agent and has a median particle size of 1.0~1.8μm; 5~10 parts of zinc borate; 2~4 parts of a composite antioxidant system, wherein the composite antioxidant system is composed of hindered phenolic primary antioxidant and phosphite auxiliary antioxidant; and 1.5~2.5 parts of crosslinking aid.

[0017] Preferably, one or two layers of refractory mica tape are spirally wrapped between the outer surface of the inner protective layer and the inner surface of the in-situ reactive self-generated ceramic composite layer.

[0018] Preferably, the fire-resistant mica tape is a composite phlogopite tape, wherein the composite phlogopite tape has phlogopite as the main component, the content of phlogopite is not less than 90% of the total mass, and the mica paper is laminated onto one or both sides of the alkali-free glass fiber cloth using high-temperature resistant silicone resin as an adhesive. The refractory mica tape is wrapped in an overlapping manner with an overlap rate of not less than 50%.

[0019] Preferably, the outer sheath is made of a thermoplastic low-smoke halogen-free flame-retardant elastomer composite, the components of which include: a matrix resin, a composite inorganic flame retardant, red phosphorus flame retardant masterbatch, and a silicon- or phosphorus-containing charring agent.

[0020] Compared with the prior art, the present invention has the following significant advantages and beneficial effects: First, the core in-situ reactive self-generated ceramic composite layer can actively respond in a fire, transforming into a hard ceramic shell with high mechanical strength, stable structure, and excellent thermal insulation performance. Its protective capability far exceeds that of the loose carbon layer formed by powder accumulation in traditional technology, and it can effectively resist the continuous impact of flames and prevent the spread of flames.

[0021] Secondly, the ceramicized shell and the internal fire-resistant mica tape form a double protection, which greatly enhances the cable's ability to maintain line integrity in a fire. It can ensure the continuous smooth operation of key power, control and information circuits under the fire resistance test conditions specified in standards such as GB / T19216.21, thus buying valuable time for personnel evacuation and emergency equipment operation.

[0022] Fourth, all structural layers of the cable are made of halogen-free materials, producing very low smoke during combustion and releasing no toxic or corrosive gases, meeting the highest requirements for safe cables in modern green buildings and critical infrastructure. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solution of a low-smoke halogen-free, high flame-retardant power cable disclosed in this invention will be described in detail and completely below with reference to specific embodiments. However, those skilled in the art should understand that the preferred embodiments described herein are merely several feasible implementations of this invention, intended to illustrate the core technology of this invention, and not to limit the scope of protection of this invention in any way. Other implementation methods obtained by those skilled in the art based on the technical solutions of this invention without creative effort should all fall within the scope of protection claimed by this invention.

[0024] The present invention provides a method for preparing a low-smoke, halogen-free, and highly flame-retardant power cable, as follows: In-situ reaction self-generated ceramic composite layer: Domestic 110-2 methyl vinyl silicone rubber was subjected to thin-pass plasticizing on an open mill with the roller temperature controlled below 40℃ for about 15 minutes until its surface was smooth and it had good roll wrapping properties. Then, the following pre-dispersed materials were slowly added in sequence: wollastonite whiskers with an average length of 30μm, an average diameter of 1.5μm, and an aspect ratio of 20:1; nano-titanium dioxide with an average particle size of 30nm; and low-melting-point glass powder with a particle size D90 of less than 12μm. Each filler was repeatedly cut and re-mixed after addition to ensure uniform dispersion. A synergistic ceramicizing and expanding foaming system is added, including microencapsulated ammonium polyphosphate with an average particle size ≤15μm. This step needs to be carried out at a lower roller temperature and a smaller roller gap to avoid premature decomposition of the foaming system due to excessive shear heat. After all powder fillers are mixed evenly, the roller gap is increased, and finally, the vulcanizing agent is evenly sprinkled in. After several rapid thin passes, the mixture is sheeted out. The resulting compound is placed in a clean, light-proof environment and allowed to stand for 24 hours to cure, thereby eliminating internal stress and allowing the components to further penetrate each other. The compound was continuously coated onto the outer surface of the inner sheath wrapped with mica tape using a cold-feed pin-type extruder with a screw diameter of Φ65. Each section of the extruder was cooled by circulating water, and the die head temperature was strictly controlled below 80℃ to prevent premature vulcanization of the rubber compound at the die head. By precisely controlling the extrusion and traction speeds, a composite layer with a uniform thickness of 2.0mm was formed. After coating, the semi-finished cable entered a 60m-long continuous vulcanization pipeline for online vulcanization in a saturated steam environment at 175℃, allowing the silicone rubber matrix to form a stable cross-linked network. Conductor insulation layer process: Magnesium hydroxide was surface-treated with a silane coupling agent in a high-speed mixer at 105°C. Ethylene-vinyl acetate copolymer and ethylene-octene copolymer resin particles and composite antioxidants are fed into the main feed port and melt-plasticized at a processing temperature of 130~150℃. Then, surface-treated magnesium hydroxide and zinc borate are forcibly added through the side feed port. Under the action of the high-shear screw combination, they are fully melt-blended and dispersed. Just before the material leaves the extruder head, a crosslinking aid, trimethylolpropane trimethacrylate, is injected through an independent metering feeder. After a brief period of weak shear mixing, the material is extruded, water-cooled, and pelletized to obtain a low-smoke, halogen-free, flame-retardant insulating material. This pellet is then passed through a Φ70 cable extruder at an extrusion temperature of 140-160℃ and a linear speed of 50m / min, tightly coating the surface of the cable conductor to form an insulation layer with a thickness of 1.2mm. The insulated wire cores that have completed the extrusion process are then passed through an electron beam irradiation accelerator device with an energy of 2.5 MeV, and the irradiation dose is controlled at 100 kGy.

[0025] The following describes the preparation of cables using raw materials with different compositions, and the testing of the cable materials. The results of these tests will be used to further illustrate the present invention.

[0026] Example 1 (Baseline Formulation): In-situ Reaction Self-Generated Ceramization Composite Layer: 100 parts methyl vinyl silicone rubber, 50 parts borosilicate glass powder (softening point 720℃, D90=12μm); 50 parts wollastonite whiskers (length-to-diameter ratio 20:1); 30 parts synergistic ceramicization system (ammonium polyphosphate: pentaerythritol: melamine = 4:1:1); 8 parts nano-TiO2 ceramicization accelerator; Conductor insulation layer: 100 parts of ethylene-vinyl acetate copolymer / ethylene-octene copolymer blend matrix in a ratio of 75:25, 140 parts of magnesium hydroxide, surface treated with aminosilane; 8 parts of zinc borate, irradiated crosslinking; Fire-resistant mica tape: Double-layer composite phlogopite tape with phlogopite content of 92% and 50% overlap with reverse wrapping; Outer sheath: 100 parts of ethylene-octene copolymer / ethylene-propylene-non-conjugated diene terpolymer blend matrix, 160 parts of aluminum hydroxide / magnesium hydroxide composite flame retardant (2:1), and 12 parts of microencapsulated red phosphorus.

[0027] Example 2 (low glass powder dosage): Difference: The dosage of low melting point glass powder in the in-situ reaction self-generated ceramic composite layer was adjusted to 40 parts, and the rest was the same as in Example 1.

[0028] Example 3 (High glass powder dosage): Difference: The dosage of low melting point glass powder in the in-situ reaction self-generated ceramic composite layer was adjusted to 60 parts, and the rest was the same as in Example 1.

[0029] Example 4 (low amount of synergistic ceramic system): Difference: The amount of synergistic ceramic system in the in-situ reaction self-generated ceramic composite layer was adjusted to 20 parts, and the rest was the same as in Example 1.

[0030] Example 5 (Dosage of high synergistic ceramic system): Difference: The dosage of the synergistic ceramic system in the in-situ reaction self-generated ceramic composite layer was adjusted to 35 parts, and the rest was the same as in Example 1.

[0031] Comparative example (traditional low-smoke halogen-free cable): Structural differences: No in-situ reactive self-generated ceramic composite layer, no refractory mica tape.

[0032] Conductor insulation layer: 100 parts EVA matrix, 180 parts magnesium hydroxide (high filler), 10 parts zinc borate.

[0033] Outer sheath: 100 parts PE matrix, 200 parts aluminum hydroxide, no red phosphorus or charring agent.

[0034] Performance test data comparison:

[0035] Conclusion Analysis: Significant advantages in physical and mechanical properties: The tensile strength (12.5~13.5MPa) and elongation at break (350~390%) of the conductor insulation layer in Examples 1~5 are much higher than those in the comparative example (7.8MPa, 190%), and the difference in the performance of the outer sheath is even more obvious. The reason is that the examples achieve the core flame-retardant function through an in-situ reaction-generated self-ceramicized composite layer, and the conductor insulation layer and outer sheath do not require high filler of inorganic flame retardants (the comparative example has a filler content of 180 parts of magnesium hydroxide), avoiding damage to the polymer matrix structure, ensuring the flexibility and mechanical integrity of the material, and solving the contradiction between high flame retardancy and high mechanical properties in traditional technologies.

[0036] Comprehensive upgrade in flame retardancy and fire resistance: Improved flame retardancy rating: LOI in all examples >35%, achieving V-0 rating in vertical burning, superior to the comparative example (LOI=32%, V-1 rating). This is primarily due to the high-temperature ceramic barrier effect of the ceramicized composite layer and the synergistic effect of the red phosphorus / charring agent in the outer sheath.

[0037] The refractory time was significantly extended: the refractory time of the examples was 100-180 min, far exceeding that of the comparative example (45 min). Among them, Example 3 with high glass powder content had the longest refractory time (180 min) because 60 parts of glass powder formed a denser molten binder phase at high temperature, and the strength of the ceramicized layer reached 9.8 MPa; while Example 4 with low synergistic system had the shortest refractory time (100 min) due to insufficient foamed carbon layer, which verified the key role of the synergistic mechanism of expansion foaming + ceramic sintering.

[0038] Superior low smoke and low toxicity characteristics: The minimum light transmittance of the example is >58%, and the HCl release is <0.14mg / g, far superior to the comparative example (30% light transmittance, 0.85mg / g HCl). This is due to: 1. All structural layers use a halogen-free formula; 2. The dense ceramic shell formed at high temperatures in the ceramicized composite layer inhibits smoke diffusion; 3. The melamine decomposition in the synergistic ceramic system releases inert gases to dilute toxic components, meeting the environmental safety requirements of high-rise buildings, data centers, and other similar locations.

[0039] The influence of component ratio on performance: Low melting point glass powder: Increasing the dosage (40→60 parts) improves the strength and refractory time of the ceramicized layer, but slightly decreases the elongation at break (390→300%). The optimal dosage is recommended to be 50~60 parts. Synergistic ceramic system: Increasing the dosage (20→35 parts) results in a thicker foamed carbon layer and improved light transmittance, but excessive dosage (35 parts) will reduce the material density, leading to a slight decrease in tensile strength. The optimal dosage is recommended to be 25~30 parts.

[0040] The above are merely preferred embodiments of the present invention and are 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 within the protection scope of the present invention.

Claims

1. A low-smoke, halogen-free, high flame-retardant power cable, comprising, from the inside out, at least one cable conductor, a conductor insulation layer covering the outer periphery of the cable conductor, an inner sheath disposed outside the conductor insulation layer, and an outer sheath covering the outermost part of the inner sheath, characterized in that, Between the inner protective layer and the outer protective sleeve, an in-situ reactive self-generated ceramic composite layer is also provided; The in-situ reactive self-generated ceramicized composite layer is a composite material layer of a hard ceramicized structure.

2. The low-smoke halogen-free high flame-retardant power cable according to claim 1, characterized in that, The material of the in-situ reaction self-generated ceramicized composite layer is a ceramicizable organosilicon composite material. The components of the ceramicizable organosilicon composite material include: organosilicon rubber matrix, low melting point glass powder, inorganic filler, and synergistic ceramicization and expansion foaming system.

3. The low-smoke halogen-free, high flame-retardant power cable according to claim 2, characterized in that, The components of the ceramizable organosilicon composite material specifically include: The silicone rubber matrix is ​​methyl vinyl silicone rubber; The low-melting-point glass powder is a borosilicate glass powder; The inorganic filler includes surface-modified wollastonite whiskers or mica powder; The synergistic ceramic formation and expansion foaming system is composed of microencapsulated ammonium polyphosphate, pentaerythritol and melamine; The ceramicizable organosilicon composite material also includes a ceramic-forming accelerator, which includes one of nano-titanium dioxide and ferric oxide.

4. The low-smoke halogen-free, high flame-retardant power cable according to claim 3, characterized in that, The components of the ceramicizable organosilicon composite material include, by mass parts: 100 parts methyl vinyl silicone rubber; 40-60 parts of low melting point glass powder; 40-60 parts of inorganic filler; 20-35 parts of the synergistic ceramic-forming and expanded foaming system; 5-10 parts of porcelain-forming accelerator.

5. A low-smoke halogen-free, high flame-retardant power cable according to claim 4, characterized in that, The vinyl molar fraction of the methyl vinyl silicone rubber is 0.15%~0.25%; The softening point temperature of the low melting point glass powder is 680~750℃, and the particle size D90 is less than 15μm. The aspect ratio of the wollastonite whiskers is greater than 15:1; In the synergistic ceramic forming and expansion foaming system, the mass ratio of ammonium polyphosphate, pentaerythritol and melamine is 4:1:

1. The degree of polymerization of the ammonium polyphosphate is greater than 1000, and it is surface microencapsulated using melamine-formaldehyde resin.

6. The low-smoke halogen-free high flame-retardant power cable according to claim 1, characterized in that, The material of the conductor insulation layer is a low-smoke halogen-free flame-retardant polyolefin composite that has been modified by irradiation crosslinking. The components of the low-smoke halogen-free flame-retardant polyolefin composite include: matrix resin, activated magnesium hydroxide, zinc borate, composite antioxidant system and crosslinking aid.

7. A low-smoke halogen-free, high flame-retardant power cable according to claim 6, characterized in that, The components of the conductor insulation layer material, by mass parts, include: 100 parts of matrix resin; the blend of ethylene-vinyl acetate copolymer and ethylene-octene copolymer is composed of ethylene-vinyl acetate copolymer and ethylene-octene copolymer in a mass ratio of (70-80):(30-20); and the ethylene-vinyl acetate copolymer has a vinyl acetate mass content of 25%~33%. 120-150 parts of activated magnesium hydroxide, wherein the activated magnesium hydroxide is surface-activated with an aminosilane coupling agent and has a median particle size of 1.0-1.8 μm; 5-10 parts of zinc borate; A 2-4 part composite antioxidant system, wherein the composite antioxidant system is composed of hindered phenolic primary antioxidants and phosphite auxiliary antioxidants; 1.5 to 2.5 parts crosslinking aid.

8. A low-smoke halogen-free, high flame-retardant power cable according to claim 1, characterized in that, Between the outer surface of the inner protective layer and the inner surface of the in-situ reactive self-ceramicized composite layer, one or two layers of refractory mica tape are spirally wrapped.

9. A low-smoke halogen-free, high flame-retardant power cable according to claim 8, characterized in that, The fire-resistant mica tape is a composite phlogopite tape, which uses phlogopite as the main component and the content of phlogopite is not less than 90% of the total mass. The mica paper is laminated onto one or both sides of the alkali-free glass fiber cloth using high-temperature resistant silicone resin as an adhesive. The refractory mica tape is wrapped in an overlapping manner with an overlap rate of not less than 50%.

10. A low-smoke, halogen-free, high flame-retardant power cable according to claim 1, characterized in that, The outer sheath is made of thermoplastic low-smoke halogen-free flame-retardant elastomer composite. The components of the thermoplastic low-smoke halogen-free flame-retardant elastomer composite include: matrix resin, composite inorganic flame retardant, red phosphorus flame retardant masterbatch, and silicon- or phosphorus-containing charring agent.

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