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CN-122011567-A - High-flame-retardance EVA (ethylene-vinyl acetate) foaming material and preparation method thereof

CN122011567ACN 122011567 ACN122011567 ACN 122011567ACN-122011567-A

Abstract

The invention discloses a high flame-retardant EVA foaming material and a preparation method thereof, and relates to the technical field of high polymer materials; the high flame-retardant EVA foaming material consists of a coated functional filler, a nitrogen-doped graphene-like carbon/cobalt nanocomposite, EVA, stearic acid, zinc stearate, zinc oxide, a foaming agent AC and dicumyl peroxide, wherein core-shell type combined filler consisting of the coated functional filler and the nitrogen-doped graphene-like carbon/cobalt nanocomposite is uniformly distributed in an EVA three-dimensional network crosslinking matrix to form a porous material with a uniform closed cell structure, the flame-retardant performance is improved by means of a physical barrier effect and a catalytic carbon formation mechanism, an efficient and stable conductive network is constructed, the antistatic performance is optimized, and the application range of the EVA foaming material is widened.

Inventors

  • LIU WEIXIANG
  • WU YANXIA
  • LIU BAIZHONG

Assignees

  • 上海莫源实业有限公司

Dates

Publication Date
20260512
Application Date
20260309

Claims (7)

  1. 1. The high flame-retardant EVA foaming material is characterized by comprising, by weight, 40-50 parts of a coated functional filler, 8-10 parts of a nitrogen-doped graphene-like carbon/cobalt nanocomposite, 200-300 parts of EVA, 2.5-2.7 parts of stearic acid, 2.5-2.7 parts of zinc stearate, 6.0-6.5 parts of zinc oxide, 12.5-13.5 parts of a foaming agent AC, 2.5-2.7 parts of dicumyl peroxide, and 10-20 parts of silane modified grafted ammonium polyphosphate and 0.8-1.0 parts of dopamine hydrochloride.
  2. 2. A method for preparing the high flame retardant EVA foaming material according to claim 1 is characterized by comprising the following steps: S1, suspending 2,2 '-bipyridine-5, 5' -dicarboxylic acid in 200mL of ethanol solution with the mass fraction of 50%, slowly adding 1mol/L potassium hydroxide aqueous solution to adjust the pH to 8.5-9.5 under the stirring of 200rpm, then adding 8.5g cobalt chloride hexahydrate, stirring for 0.5-1h, transferring into a polytetrafluoroethylene-lined high-pressure reaction kettle, reacting for 24h at 110-120 ℃, centrifuging, alternately washing a precipitate with deionized water and methanol for 3 times, drying in a 60 ℃ vacuum drying box for 12h, placing the obtained precursor in a tubular furnace, and performing heat treatment for 1-2h at 500-600 ℃ under the protection of nitrogen to obtain the nitrogen-doped graphene-like carbon/cobalt nanocomposite; S2, weighing 8.0-10.0g of the nitrogen-doped graphene-like carbon/cobalt nanocomposite material in the step S1, placing the weighed 8.0-10.0g in 150mL of deionized water, adding 1.2g of sodium dodecyl sulfate, performing ultrasonic dispersion for 50-60min to form a dispersion liquid for standby, drying 40.0-50.0g of coating functional filler at 60 ℃ for 1-2h, dispersing the coating functional filler in 300mL of deionized water, performing ultrasonic treatment for 20-30min, stirring at 300-500rpm, adding the dispersion liquid, regulating pH to 8.0-9.0 by using ammonia water, reacting at room temperature for 12-24h, centrifuging, washing the precipitate with 60-70 ℃ for 3 times by using absolute ethyl alcohol, drying, grinding, sieving with a 80-100 mesh sieve to obtain a combined filler for standby, placing 200.0-300.0gEVA, 2.5-2.7g of stearic acid, 2.5-2.7g of zinc stearate, 6.0-6.5g of zinc oxide in a mixer, performing melt blending treatment for 2min, adding 3.5-3 MPa, mixing, granulating at 3-5 ℃ for 2.5-3 min, cooling at 3-10 ℃ for 2MPa, cooling at room temperature for 1-3min, granulating, cooling at 1-10 ℃ for 2.5-3 MPa, and placing the foamed material in a die, cooling for 1-3-10 min, granulating, and cooling at 1-5 ℃ for 1.5-5 min, and cooling to obtain the foamed material.
  3. 3. The method for producing a high flame retardant EVA foam of claim 2, wherein the amount of 2,2 '-bipyridine-5, 5' -dicarboxylic acid added in step S1 is 8.7g.
  4. 4. The method of preparing a high flame retardant EVA foam material of claim 3, wherein in step S2, the temperature of the feeding section is 120-140 ℃, the temperature of the melting section is 150-160 ℃, the temperature of the discharging section is 140-150 ℃ and the rotation speed is 80-100rpm.
  5. 5. The method for preparing the high flame retardant EVA foaming material of claim 4, wherein the preparation method of the coated functional filler comprises the following steps: (1) Adding 3-glycidoxypropyl trimethoxy silane into 200-250mL of ethanol solution with the mass fraction of 90%, regulating the pH to 4.0-5.0 by acetic acid, stirring for 30-50min under the oil bath at 40-50 ℃ to obtain hydrolysate for standby, adding 80.0-100.0g of piperazine pyrophosphate into the hydrolysate for 5 times, performing ultrasonic dispersion for 15-20min, stirring and reacting for 2-3h at 70 ℃ under the nitrogen atmosphere, centrifuging, repeatedly washing the precipitate by absolute ethyl alcohol for many times until the eluent is dried and has no residue and the pH is neutral, and finally drying the washed product in a 60 ℃ vacuum drying box for 10-12h to obtain silane modified grafted ammonium polyphosphate; (2) And (3) weighing 10.0-20.0g of the silane modified grafted ammonium polyphosphate in the step (1), adding the silane modified grafted ammonium polyphosphate into 400mL of ethanol solution with the mass fraction of 30%, carrying out ultrasonic treatment for 30-40min, adding dopamine hydrochloride and 2.0-2.5g of tris (hydroxymethyl) aminomethane hydrochloride under the stirring condition, regulating the pH value of the mixed solution to 8.5 by using ammonia water before the dopamine hydrochloride is completely added, carrying out stirring reaction for 30-36h at room temperature, centrifuging after the reaction is finished, washing the precipitate by using deionized water until the supernatant is colorless, and carrying out freeze drying to obtain the coated functional filler.
  6. 6. The method of producing a high flame retardant EVA foam according to claim 5, wherein in the step (1), 3-glycidoxypropyl trimethoxysilane is added in an amount of 3.0 to 4.0g.
  7. 7. The method of producing a high flame retardant EVA foam material of claim 6, wherein in step (2), the amount of dopamine hydrochloride added is 0.8-1.0g.

Description

High-flame-retardance EVA (ethylene-vinyl acetate) foaming material and preparation method thereof Technical Field The invention belongs to the technical field of high polymer materials, and particularly relates to a high flame-retardant EVA foaming material and a preparation method thereof. Background Ethylene-vinyl acetate copolymer (EVA) is an important thermoplastic elastomer, and is formed by copolymerizing ethylene monomer and vinyl acetate monomer, and the introduction of the vinyl acetate monomer reduces the crystallinity of the material, so that the material has good processability, flexibility, low-temperature toughness, environmental stress cracking resistance, weather resistance and the like, and is widely applied to various fields such as packaging, building, automobiles and the like, but the high flammability of EVA makes the EVA be in potential safety hazard in many application scenes, so that the development of efficient flame retardant to improve the flame retardant performance of the EVA is particularly important. The prior art mainly has the following problems: In the application of EVA foaming materials, the problem of insufficient flame retardant property and antistatic property is still commonly faced, and the wider and safer use of the EVA foaming materials is limited. Disclosure of Invention Aiming at the situation, in order to overcome the defects of the prior art, the invention provides a high flame retardant EVA foaming material, which comprises, by weight, 40-50 parts of a coating type functional filler, 8-10 parts of a nitrogen doped graphene-like carbon/cobalt nanocomposite, 200-300 parts of EVA, 2.5-2.7 parts of stearic acid, 2.5-2.7 parts of zinc stearate, 6.0-6.5 parts of zinc oxide, 12.5-13.5 parts of a foaming agent AC and 2.5-2.7 parts of dicumyl peroxide. The coating type functional filler is prepared from the following components in parts by weight, 10-20 parts of silane modified grafted ammonium polyphosphate and 0.8-1.0 part of dopamine hydrochloride. The preparation method of the coated functional filler specifically comprises the following steps: (1) Adding 3-glycidoxypropyl trimethoxysilane into 200-250mL of ethanol solution with the mass fraction of 90%, regulating the pH value to 4.0-5.0 by acetic acid, stirring for 30-50min under the oil bath at 40-50 ℃ to obtain hydrolysate for standby, adding 80.0-100.0g of piperazine pyrophosphate into the hydrolysate for 5 times, ultrasonically dispersing for 15-20min, stirring and reacting for 2-3h under the nitrogen atmosphere at 70 ℃, centrifuging, repeatedly washing the precipitate by absolute ethyl alcohol for many times until the eluent is dried and has no residue and has neutral pH value, finally, drying the washed product in a 60 ℃ vacuum drying box for 10-12h, forming a three-dimensional reticular organic silicon polymer shell layer anchored by Si-O-P bonds by taking Si-O-Si as a skeleton on the surface of piperazine pyrophosphate particles, anchoring core flame retardant components in a polymer network, keeping the piperazine pyrophosphate layer for a longer time in an expanded carbon layer during combustion, inhibiting molten drops, thereby improving the quality and stability of the carbon layer, improving the compatibility with EVA matrix, ensuring that the ammonium pyrophosphate particles are uniformly dispersed in the matrix, avoiding the formation of an ion-modified conductive filler in the sea-state, and forming a static electricity-conductive filler, and forming a more compact and static electricity-resistant modified polymer network; (2) Weighing 10.0-20.0g of the silane modified grafted ammonium polyphosphate in the step (1), adding the silane modified grafted ammonium polyphosphate into 400mL of ethanol solution with the mass fraction of 30%, carrying out ultrasonic treatment for 30-40min, adding dopamine hydrochloride and 2.0-2.5g of tris (hydroxymethyl) aminomethane hydrochloride under the stirring condition, regulating the pH value of the mixed solution to 8.5 by ammonia before the dopamine hydrochloride is completely added, stirring and reacting for 30-36h at room temperature, centrifuging after the reaction is finished, washing the precipitate by deionized water until the supernatant is colorless, freeze-drying, taking the polydopamine coating as the outermost surface layer, anchoring a core flame retardant at a combustion position through adhesiveness, preventing premature falling-off failure, delaying the transmission of heat and decomposition products, playing a role in synergetic enhancement on the flame retardant property, simultaneously, forming a thin hydration layer on the surface of the filler, providing a moisture-based ion conducting channel as a carrier, further improving the antistatic property, and obtaining the coated functional filler; Preferably, in the step (1), the addition amount of 3-glycidoxypropyl trimethoxysilane is 3.0-4.0g, and 3-glycidoxypropyl trimethoxysilane is used as a