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CN-121306681-B - Preparation process of high-flame-retardance cable

CN121306681BCN 121306681 BCN121306681 BCN 121306681BCN-121306681-B

Abstract

The invention relates to the technical field of cables, in particular to a preparation process of a high-flame-retardance cable. The process adopts low-density polyethylene and ethylene-vinyl acetate copolymer as a matrix, grafts silane by double screw extrusion, and then introduces nano composite flame retardant based on magnesium-aluminum layered double hydroxide, phosphine compound, cage-shaped polysilsesquioxane and the like, and proper amount of magnesium hydroxide, aluminum hydroxide and zinc borate to realize synergistic flame retardance and smoke suppression. The nano composite flame retardant can remarkably improve interface combination and dispersibility through multiple surface modification and function coordination, form a compact carbonization and ceramic layer, and realize low smoke, low combustion spreading and stable low dielectric property.

Inventors

  • ZHANG SHULEI

Assignees

  • 东莞市帝深电子有限公司

Dates

Publication Date
20260508
Application Date
20250929

Claims (9)

  1. 1. The preparation process of the high-flame-retardance cable is characterized by comprising the following steps of: (1) Sequentially adding low-density polyethylene resin, ethylene-vinyl acetate copolymer resin, vinyl triethoxysilane, dicumyl peroxide and an antioxidant into a main feed inlet of a double-screw extruder, melting and mixing, and starting vacuum devolatilization to obtain a silane grafted polyethylene matrix material; (2) The silane grafted polyethylene matrix material is rotationally fed into a double-screw extruder, nano composite flame retardant, magnesium hydroxide, aluminum hydroxide and zinc borate are added into a main feed port, deionized water is sprayed into the main feed port by an atomizing pump, and the main feed port is melt-blended, extruded and cooled to obtain cable insulating material particles; (3) Extruding cable insulating material particles on a conductor under an extruding machine, then performing steam crosslinking to obtain the cable with high flame retardance, The weight ratio of the low-density polyethylene resin, the ethylene-vinyl acetate copolymer resin, the vinyl triethoxysilane, the dicumyl peroxide and the antioxidant in the step (1) is 8000:250-550:60-130:15-35:8-24; Dissolving 2-carboxyethyl phenyl phosphonic acid in a sodium hydroxide aqueous solution, adding magnesium-aluminum layered double hydroxide to prepare magnesium-aluminum layered double hydroxide aqueous slurry containing phosphonate, adding trisilyl phenyl-cage polysilsesquioxane, N-phenyl amino propyl-cage silsesquioxane, 3-glycidoxypropyl triethoxysilane, 9, 10-dihydro-9-oxo-10-phosphaphenanthrene-10-oxide and dibutyltin dilaurate into a mixed solution of absolute ethyl alcohol and deionized water to prepare polysilsesquioxane composite reaction solution, adding the polysilsesquioxane composite reaction solution into the magnesium-aluminum layered double hydroxide aqueous slurry containing phosphonate, adding ammonium polyphosphate and pentaerythritol, stirring for 100-140min at 60-70 ℃, performing reduced pressure distillation, and performing vacuum drying to obtain the nano composite flame retardant; The weight ratio of the 2-carboxyethyl phenylphosphonic acid, the magnesium aluminum layered double hydroxide, the trisilanolphenyl-cage polysilsesquioxane, the N-phenylaminopropyl-cage silsesquioxane, the 3-glycidoxypropyl triethoxysilane, the 9, 10-dihydro-9-oxo-10-phosphaphenanthrene-10-oxide, the dibutyl tin dilaurate, the ammonium polyphosphate and the pentaerythritol is 240-400:800-1200:45-75:45-75:45-75:90-150:4.7-7.5:720-1200:300-500.
  2. 2. The process for preparing a high flame retardant cable according to claim 1, wherein the low density polyethylene resin in the step (1) is ExxonMobil LD 2023fl. Bw and the ethylene-vinyl acetate copolymer resin is ELVAX 260.
  3. 3. The process for preparing a high flame retardant cable according to claim 1, wherein the antioxidant in the step (1) is a mixture of antioxidant 1010 and antioxidant 168 in a weight ratio of 1:1.
  4. 4. The process for preparing a high flame retardant cable according to claim 1, wherein the temperature of each zone of the twin screw extruder in step (1) is 150-185 ℃ and the rotation speed is 180-260rpm.
  5. 5. The process for preparing a high flame retardant cable according to claim 1, wherein the weight ratio of the nanocomposite flame retardant, magnesium hydroxide, aluminum hydroxide, zinc borate and deionized water in the step (2) is 2000-3200:150-350:75-180:30-90:30-90.
  6. 6. The process for preparing a high flame retardant cable according to claim 1, wherein the magnesium hydroxide in the step (2) is MAGNIFIN H-5A in type, the aluminum hydroxide is MARTINAL OL-104LEO in type, and the zinc borate is fibriak ZB in type.
  7. 7. The process for preparing a high flame retardant cable according to claim 1, wherein the temperature of each zone of the twin screw extruder in the step (2) is 160-185 ℃ and the rotation speed is 200-280rpm, and the residence time is 3-5min.
  8. 8. The process for preparing a high flame retardant cable according to claim 1, wherein the extruder in the step (3) has a barrel temperature of 140 to 185 ℃ and a head temperature of 160 to 180 ℃.
  9. 9. The process for preparing a high flame retardant cable according to claim 1, wherein the temperature of the steam crosslinking in the step (3) is 175-195 ℃ for 15-25min.

Description

Preparation process of high-flame-retardance cable Technical Field The invention relates to the technical field of cables, in particular to a preparation process of a high-flame-retardance cable. Background The cable is used as an important carrier for modern power transmission and information communication, and the safety performance of the cable is directly related to national economy construction and life and property safety of people. Along with the acceleration of urban process and the continuous increase of power demand, cables are increasingly widely applied to closed spaces such as buildings, tunnels, subways and the like, and once a fire disaster occurs, huge economic loss can be caused, and serious casualties can be caused. Therefore, improving the flame retardant properties of cables has become an urgent need for development of the cable industry. Conventional cable flame retardant technology relies mainly on the addition of large amounts of inorganic flame retardants such as aluminum hydroxide (ATH), magnesium Hydroxide (MH), etc., in the polymer matrix. These inorganic flame retardants exert flame retarding effects mainly by an endothermic dehydration mechanism, but have obvious technical limitations. Firstly, to achieve the ideal flame retardant effect, more than 50% of inorganic flame retardant is usually required to be added, which not only increases the weight and cost of the cable significantly, but also causes the drastic decrease of the mechanical properties of the cable, and key indexes such as tensile strength, elongation at break and the like are difficult to meet the use requirements. And secondly, the introduction of a large amount of inorganic filler can destroy the continuity of a polymer matrix, stress concentration is generated at an interface, the cable is easy to crack under the stress effects of bending, stretching and the like, and the service life of the cable is seriously influenced. More importantly, the traditional inorganic flame retardant has poor compatibility with a polymer matrix, and is easy to generate phase separation and migration phenomena in the preparation and use processes of the cable. The interface instability not only reduces flame retardant efficiency, but also causes fluctuation of dielectric properties, and has adverse effects on the electrical properties of the cable. Particularly in the high-frequency signal transmission scene, the instability of the dielectric constant can lead to signal attenuation and distortion, and seriously affect the communication quality. In addition, conventional flame retardant systems often accompany the generation of large amounts of smoke during the combustion process, which can not only impede personnel evacuation, but also cause secondary injury. In recent years, researchers have begun to explore new flame retardant technology routes, where Intumescent Flame Retardants (IFR) have received widespread attention for their unique char-forming flame retardant mechanism. IFR systems typically consist of an acid source, a char source, and a blowing agent, which when heated, is capable of forming a porous, foamed carbon layer that serves to insulate heat, oxygen, and prevent the escape of flammable gases. However, the conventional IFR system still has the problems of insufficient stability of a char formation layer, easiness in cracking at high temperature and the like, and limits the application of the IFR system in high-performance cables. With the development of nanotechnology, nano-modified flame retardants are becoming a research hotspot. Layered Double Hydroxides (LDHs) are an important class of nanomaterial with unique layered structures and controllable compositions, showing great potential in the flame retardant field. The LDH not only has the heat absorption and dehydration functions of the traditional inorganic flame retardant, but also can form an oxide ceramic layer at high temperature, thereby providing an additional barrier effect. However, the dispersibility and interfacial compatibility of LDHs in polymers remain key factors limiting their use. Cage Polysilsesquioxane (POSS) has been attracting attention as an organic-inorganic hybrid material due to its unique cage structure and functionalizable nature. The silicone cage core in the POSS molecule imparts excellent thermal stability thereto, while the organic functional groups provide compatibility with the polymer matrix. Through reasonably designing the organic functional groups of POSS, the synergistic effect of the POSS and the flame retardant can be realized, but how to construct a stable composite interface structure is still a technical problem. The comprehensive analysis of the prior art can find that although various flame retardant technologies have advantages, the fundamental contradiction that the flame retardant performance is difficult to be compatible with mechanical and dielectric properties exists in the cable application. In particular in app