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CN-122011482-A - Preparation method of environment-friendly halogen-free low-smoke flame-retardant silicone rubber cable insulating material

CN122011482ACN 122011482 ACN122011482 ACN 122011482ACN-122011482-A

Abstract

The invention discloses a preparation method of an environment-friendly halogen-free low-smoke flame-retardant silicon rubber cable insulating material, and relates to the technical field of silicon rubber cable insulating materials. According to the invention, by adopting the hydroxyapatite inner core-boron nitride outer shell composite filler and matching with the ammonium polyphosphate and silazane resin compound flame-retardant system, and combining the synergistic effect of the dynamic compatibilizer and the hydroxyl-terminated polybutadiene siloxane segmented copolymer, the synchronous promotion of halogen-free low smoke and high flame retardance of the material is realized.

Inventors

  • Liang Lianji
  • LI YUEWEN

Assignees

  • 江苏天力电缆有限公司

Dates

Publication Date
20260512
Application Date
20251211

Claims (10)

  1. 1. The preparation method of the environment-friendly halogen-free low-smoke flame-retardant silicone rubber cable insulating material is characterized by comprising the following steps of (1) taking 96-104 parts by weight of methyl vinyl vulcanized silicone rubber raw rubber, 4-7 parts by weight of composite filler, 9-11 parts by weight of a flame-retardant system compounded by ammonium polyphosphate and silicone nitrogen resin, 0.6-1.1 parts by weight of a dynamic compatibilizer, 0.9-1.4 parts by weight of hydroxyl-terminated polybutadiene siloxane block copolymer and 0.12-0.28 part by weight of an organotin titanate composite catalyst; the composite filler is hydroxyapatite inner core-boron nitride outer shell composite filler; sequentially adding methyl vinyl vulcanized silicone rubber raw rubber, composite filler, dynamic compatibilizer, hydroxyl-terminated polybutadiene siloxane block copolymer, ammonium polyphosphate and silicone nitrogen resin compound flame-retardant system and 50% of organic tin titanate composite catalyst under the conditions of 58-63 ℃ and 0.088-0.072 MPa of vacuum degree, and carrying out staged mixing to obtain premixed rubber; Placing the premixed rubber obtained in the step (2) in a supercritical CO 2 environment with the temperature of 34-46 ℃ and the pressure of 8-12 MPa, preserving heat and pressure for 20-30 min, and introducing inert nitrogen for replacement after pressure relief to obtain the pretreated premixed rubber; And (4) adding the rest 50% of organic tin titanate composite catalyst into the pre-treated pre-mixed glue obtained in the step (3), and vulcanizing to obtain the vulcanized silicone rubber cable insulating material.
  2. 2. The preparation method of the environment-friendly halogen-free low-smoke flame-retardant silicone rubber cable insulating material according to claim 1, wherein the mass fraction of vinyl content of the methyl vinyl vulcanized silicone rubber raw rubber in the step (1) is 0.16% -0.24%.
  3. 3. The preparation method of the environment-friendly halogen-free low-smoke flame-retardant silicone rubber cable insulating material is characterized in that the composite filler in the step (1) has the following structure that the core is hydroxyapatite microsphere, the particle size of the microsphere is 1.6-2.1 mu m, and the porosity is 34-41%; The shell is an amino modified boron nitride nano sheet layer, the thickness of the nano sheet layer is 6 nm-8 nm, and the number of layers is 3-5; the inner core and the outer shell are bonded through gamma-aminopropyl triethoxysilane, and the grafting rate of the gamma-aminopropyl triethoxysilane on the surface of the composite filler is 68% -95%.
  4. 4. The preparation method of the environment-friendly halogen-free low-smoke flame-retardant silicone rubber cable insulation material according to claim 1, wherein the dynamic compatibilizer in the step (1) is a physical blend of gamma-chloropropyl methyl dimethoxy silane and maleic anhydride grafted ethylene-vinyl acetate copolymer, and the molar ratio of gamma-chloropropyl methyl dimethoxy silane to maleic anhydride grafted ethylene-vinyl acetate copolymer is 1:0.72-1:0.88.
  5. 5. The preparation method of the environment-friendly halogen-free low-smoke flame-retardant silicone rubber cable insulating material is characterized in that in the step (1), parameters of a flame-retardant system compounded by ammonium polyphosphate and silicone resin are as follows, wherein the polymerization degree n=1020-1180 of the ammonium polyphosphate, the mass fraction of nitrogen content of the silicone resin is 39% -41%, and the mass ratio of the ammonium polyphosphate to the silicone resin is 1:1.42-1:1.58.
  6. 6. The preparation method of the environment-friendly halogen-free low-smoke flame-retardant silicone rubber cable insulating material according to claim 1 is characterized in that the parameters of the hydroxyl-terminated polybutadiene siloxane block copolymer in the step (1) are as follows, wherein the block ratio is hydroxyl-terminated polybutadiene chain segments, siloxane chain segments = 2:0.92-2:1.08; The number average molecular weight is 3.0X10 4 ～5.0×10 4 Da; the mass ratio of the hydroxyl-terminated polybutadiene siloxane block copolymer to the composite filler in the step (1) is 1:4.2-1:5.8.
  7. 7. The preparation method of the environment-friendly halogen-free low-smoke flame-retardant silicone rubber cable insulating material is characterized in that the parameters of the organotin titanate composite catalyst in the step (1) are as follows, wherein the components comprise dibutyltin dilaurate and tetrabutyl titanate, and the mass fraction of the purity of the dibutyltin dilaurate is 99.6% -99.8%; the mass hydrolysis degree of the tetrabutyl titanate is 14% -21%; The molar ratio of the dibutyl tin dilaurate to the tetrabutyl titanate is 1:1.12-1:1.28.
  8. 8. The preparation method of the environment-friendly halogen-free low-smoke flame-retardant silicone rubber cable insulating material according to claim 1, which is characterized in that the specific process of staged mixing in the step (2) is as follows: Adding methyl vinyl vulcanized silicone rubber raw rubber and composite filler, and mixing for 7.5 min-8.5 min at a rotating speed of 30 r/min-36 r/min; adding a dynamic compatibilizer and a hydroxyl-terminated polybutadiene siloxane segmented copolymer, increasing the rotating speed to 44 r/min-50 r/min, and mixing for 3.2 min-3.8 min; adding an ammonium polyphosphate and silazane compound flame-retardant system and 50% of an organotin titanate compound catalyst, maintaining the rotating speed of 44-50 r/min, heating to 87-93 ℃ at the same time, and mixing for 4.5-5.5 min to obtain the premixed rubber.
  9. 9. The preparation method of the environment-friendly halogen-free low-smoke flame-retardant silicone rubber cable insulating material is characterized in that the flow rate of inert nitrogen in the step (3) is 1.2L/min-1.8L/min, and the replacement time is 8-12 min; In the replacement process, the temperature of the premixed rubber material treated by the supercritical CO 2 is maintained at 34-46 ℃.
  10. 10. The preparation method of the environment-friendly halogen-free low-smoke flame-retardant silicone rubber cable insulating material is characterized in that in the step (4), a gradient temperature-pressure system is adopted for vulcanization, and the method is characterized in that the temperature is kept at 117-123 ℃ and the pressure is kept at 0.95-1.05 MPa for 4.5-5.5 min; Heating to 157-163 ℃ at a heating rate of 4.5-5.5 ℃ per minute, and simultaneously adjusting the pressure to 1.35-1.45 MPa, and keeping for 7.5-8.5 min; cooling to 137-143 ℃ at a cooling rate of 1.5-2.5 ℃ per minute, and simultaneously adjusting the pressure to 1.15-1.25 MPa, and keeping for 2.5-3.5 min; naturally cooling to room temperature to finish vulcanization.

Description

Preparation method of environment-friendly halogen-free low-smoke flame-retardant silicone rubber cable insulating material Technical Field The invention relates to the technical field of silicon rubber cable insulation materials, in particular to a preparation method of an environment-friendly halogen-free low-smoke flame-retardant silicon rubber cable insulation material. Background The cable insulating material has the core functions of isolating the cable conductor from the external environment and other conductors so as to ensure safe electric energy transmission, preventing current leakage through the electric insulating property, avoiding short circuit or electric shock risks, providing physical protection, resisting external mechanical damage, moisture invasion and chemical corrosion, reducing the influence of external factors on the conductor, prolonging the service life of the cable and ensuring the stable operation of the cable under complex conditions. In the prior art, for cable insulation materials, the traditional flame-retardant system relies on halogen-containing components, and toxic and harmful gases and corrosive substances are released during combustion, so that the cable insulation materials are harmful to human health and pollute the environment, do not meet the current environmental protection requirements, and the flame-retardant efficiency of the materials is often greatly reduced in pursuit of environmental protection or halogen removal, and meanwhile, the problems of poor smoke suppression effect and high smoke concentration during combustion are accompanied. Based on the method, the invention provides a preparation method of an environment-friendly halogen-free low-smoke flame-retardant silicone rubber cable insulating material. Disclosure of Invention The invention aims to provide a preparation method of an environment-friendly halogen-free low-smoke flame-retardant silicon rubber cable insulating material, which adopts a hydroxyapatite inner core-boron nitride outer shell composite filler, a flame-retardant system compounded by ammonium polyphosphate and silicon nitrogen resin, combines the synergistic effect of a dynamic compatibilizer and a hydroxyl-terminated polybutadiene siloxane segmented copolymer, synchronously improves flame-retardant efficiency and smoke suppression effect on a halogen-free basis, introduces a supercritical CO 2 pretreatment process, optimizes the dispersibility of the internal components of the material in a staged mixing mode, improves structural uniformity, adopts an organotin titanate composite catalyst to adopt a two-time adding strategy, designs a gradient temperature-pressure vulcanization system, accurately regulates and controls the crosslinking density of the material, and finally realizes the synchronous improvement of the material on environment friendliness, flame retardance, mechanical property, insulating property and ageing resistance. In order to achieve the above purpose, the present invention provides the following technical solutions: The preparation method of the environment-friendly halogen-free low-smoke flame-retardant silicone rubber cable insulating material comprises the following steps of (1) taking 96-104 parts by weight of methyl vinyl vulcanized silicone rubber raw rubber, 4-7 parts by weight of composite filler, 9-11 parts by weight of a flame-retardant system compounded by ammonium polyphosphate and silicone nitrogen resin, 0.6-1.1 parts by weight of a dynamic compatibilizer, 0.9-1.4 parts by weight of hydroxyl-terminated polybutadiene siloxane block copolymer and 0.12-0.28 part by weight of an organotin titanate composite catalyst; the composite filler is hydroxyapatite inner core-boron nitride outer shell composite filler; sequentially adding methyl vinyl vulcanized silicone rubber raw rubber, composite filler, dynamic compatibilizer, hydroxyl-terminated polybutadiene siloxane block copolymer, ammonium polyphosphate and silicone nitrogen resin compound flame-retardant system and 50% of organic tin titanate composite catalyst under the conditions of 58-63 ℃ and 0.088-0.072 MPa of vacuum degree, and carrying out staged mixing to obtain premixed rubber; Placing the premixed rubber obtained in the step (2) in a supercritical CO 2 environment with the temperature of 34-46 ℃ and the pressure of 8-12 MPa, preserving heat and pressure for 20-30 min, and introducing inert nitrogen for replacement after pressure relief to obtain the pretreated premixed rubber; And (4) adding the rest 50% of organic tin titanate composite catalyst into the pre-treated pre-mixed glue obtained in the step (3), and vulcanizing to obtain the vulcanized silicone rubber cable insulating material. Preferably, the vinyl content of the methyl vinyl vulcanized silicone rubber raw rubber in the step (1) is 0.16% -0.24% by mass. Preferably, the composite filler in the step (1) has the structure that the inner core is hydroxyapatite microsphere, the partic