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CN-121991429-A - Heat-shrinkable material, heat-shrinkable tube and preparation method thereof

CN121991429ACN 121991429 ACN121991429 ACN 121991429ACN-121991429-A

Abstract

The invention provides a heat-shrinkable material, a heat-shrinkable tube and a preparation method thereof, wherein the heat-shrinkable material comprises, by weight, 80-90 parts of ethylene-vinyl acetate copolymer, 10-20 parts of terpolymer of ethylene, propylene and non-conjugated diene, 3-5 parts of copolymer compatilizer, 50-60 parts of inorganic halogen-free flame retardant, 15-20 parts of flame retardant synergist, 3-5 parts of antioxidant and 2-4 parts of processing aid. The comprehensive technical advantages of high GWFI (960 ℃) grade +V0 flame retardance +excellent mechanical property +excellent processability are realized through component composite design and process optimization, and a more reliable material solution is provided for circuit insulation protection in the high-end field.

Inventors

  • ZHANG CANBING
  • PENG XIANYANG
  • WANG ZHI
  • QIAO MENGYA
  • DU WEIYI

Assignees

  • 上海长园电子材料有限公司

Dates

Publication Date
20260508
Application Date
20251229

Claims (14)

  1. 1. The heat-shrinkable material is characterized by comprising the following components in parts by weight:
  2. 2. The heat shrink material of claim 1, wherein the ethylene vinyl acetate copolymer has a melt index of 1.5 to 5 grams per minute and a vinyl acetate monomer content of 12% to 30%.
  3. 3. The heat shrink material of claim 1, wherein the terpolymer of ethylene, propylene and a non-conjugated diene has an ethylene content of 65% to 75% and a propylene content of 24% to 34%.
  4. 4. The heat shrink material of claim 1, wherein the copolymer compatibilizer is a maleic anhydride graft copolymer having a maleic anhydride comonomer grafting ratio of 0.5% to 1.2%.
  5. 5. The heat-shrinkable material of claim 1, wherein the inorganic halogen-free flame retardant is formed by compounding metal hydrate and red phosphorus according to a weight ratio of 5:1.
  6. 6. The heat-shrinkable material of claim 5, wherein the metal hydrate is formed by compounding modified magnesium hydroxide and modified aluminum hydroxide according to a weight ratio of 1:1.
  7. 7. The heat-shrinkable material of claim 1, wherein the flame retardant synergist is compounded by nano silicate flame retardant, organosilicon flame retardant and carbon black according to a weight ratio of 1:1:0.5.
  8. 8. The heat shrink material of claim 7, wherein the nano silicate flame retardant comprises any one or a combination of two of surface modified montmorillonite or sepiolite.
  9. 9. The heat shrink material of claim 1, wherein the processing aid comprises any one or a combination of two of silicone masterbatch, silicone powder, or zinc stearate.
  10. 10. A method for preparing a heat-shrinkable material, which is characterized in that the heat-shrinkable material according to any one of claims 1 to 9 is taken for premixing to obtain a mixture, and the mixture is extruded and granulated by a twin-screw extruder after being mixed by an internal mixer.
  11. 11. The method according to claim 10, wherein the pre-mixing is preceded by drying at a temperature of 50-60 ℃ for a time of 1-5 hours, and the water content is controlled below 0.3%.
  12. 12. The method according to claim 10, wherein the internal mixer has a discharge temperature of 120-130 ℃, and the melt extrusion conditions include a feed stage temperature of 100-110 ℃, a compression stage temperature of 110-120 ℃, a homogenization stage temperature of 120-130 ℃ and a screw speed of 250-300r/min.
  13. 13. A heat shrinkable tube prepared using the heat shrinkable material of any one of claims 1 to 9.
  14. 14. A heat shrink tube manufacturing method, characterized in that the heat shrink tube is obtained by taking the heat shrink material according to any one of claims 1 to 9, extrusion molding, irradiation crosslinking, and expansion molding.

Description

Heat-shrinkable material, heat-shrinkable tube and preparation method thereof Technical Field The invention relates to the technical field of high polymer materials, in particular to a heat-shrinkable material, a heat-shrinkable tube and a preparation method thereof. Background The irradiation crosslinking modified polyolefin heat-shrinkable tube is used as an insulating protection component of a circuit system core, is widely applied to a plurality of key fields such as aerospace, electronic power, automobiles, high-speed rails and the like, and has the core functions of providing insulating protection for a circuit and resisting environmental influence under various working conditions. In the actual service process, a large amount of heat is often generated by the circuit due to overlarge load or short circuit, and in extreme cases, plastic insulating parts such as heat shrinkage tubes and the like can burn and burn, so that the flame-retardant protection performance is one of the core technical indexes of the material. The halogen-free flame-retardant modified heat-shrinkable material and the heat-shrinkable tube prepared by the halogen-free flame-retardant modified heat-shrinkable material in the prior art have clear performance limitations that the Glow Wire Flammability Index (GWFI) can only reach 700-750 ℃, and in order to realize the UL94-V0 level flame-retardant effect, more than 50% of flame retardant must be added. The core disadvantage of the technical scheme is that the addition of the high-proportion flame retardant can directly lead to the remarkable reduction of mechanical properties (such as tensile strength and elongation at break) and processability of materials, and the use reliability and the production and processing requirements under complex working conditions are difficult to meet. With the rapid development of high and new technologies such as new energy automobiles and Artificial Intelligence (AI), the requirements of an electric power system on the load capacity are continuously improved, a heat shrinkage tube serving as a key insulation protection component faces a higher-level flame retardant protection challenge, and products with high Glow Wire Flammability Index (GWFI) are required to be developed so as to ensure that a circuit system can maintain stable protection capacity under high load even in a short circuit glowing state. The glowing filament flammability index (GWFI) of the existing halogen-free flame-retardant modified heat-shrinkable material and heat-shrinkable tube is only 700-750 ℃, so that the requirements of high flame-retardant protective capability under extreme working conditions such as high load and short circuit of a power system in the high-tech fields such as new energy automobiles, artificial intelligence and the like cannot be matched, and the protective effect is difficult to be continuously exerted under the glowing state of a circuit. In addition, in the prior art, in order to enable the heat shrinkage material to reach the UL94-V0 grade flame retardant grade, more than 50% of flame retardant is required to be added, the introduction of the high-proportion flame retardant leads to the remarkable reduction of mechanical properties (such as tensile strength and elongation at break) of the material, meanwhile, the processing difficulty is increased, the molding quality and the production efficiency of the product are affected, and the balance of the flame retardant performance, the use performance and the processing performance cannot be considered. Disclosure of Invention In view of the above, the invention aims to solve the technical problems of insufficient flame retardant protection level, mechanical property and processing property degradation and the like of the traditional heat-shrinkable material. The invention provides a heat-shrinkable material which comprises, by weight, 80-90 parts of an ethylene-vinyl acetate copolymer, 10-20 parts of a terpolymer of ethylene, propylene and non-conjugated diene, 3-5 parts of a copolymer compatilizer, 50-60 parts of an inorganic halogen-free flame retardant, 15-20 parts of a flame retardant synergist, 3-5 parts of an antioxidant and 2-4 parts of a processing aid. Alternatively, the ethylene vinyl acetate copolymer has a melt index of 1.5 to 5 grams per minute and a vinyl acetate monomer content of 12% to 30%. Alternatively, a terpolymer of ethylene, propylene and a non-conjugated diene having an ethylene content of 65% to 75% and a propylene content of 24% to 34%. Optionally, the copolymer compatibilizer is a maleic anhydride graft copolymer, wherein the maleic anhydride comonomer graft ratio is 0.5% to 1.2%. Optionally, the inorganic halogen-free flame retardant is formed by compounding metal hydrate and red phosphorus according to the weight ratio of 5:1. Optionally, the metal hydrate is formed by compounding modified magnesium hydroxide and modified aluminum hydroxide according to the weight ratio of 1: