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CN-122011514-A - Double-shell microcapsule modified magnesium hydroxide flame retardant and preparation method and application thereof

CN122011514ACN 122011514 ACN122011514 ACN 122011514ACN-122011514-A

Abstract

The invention discloses a double-shell microcapsule modified magnesium hydroxide flame retardant, a preparation method and application thereof, wherein the flame retardant takes magnesium hydroxide as a core, the core is sequentially coated with an inner wall formed by 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and an outer wall formed by ethyl cellulose. The preparation method comprises the steps of dissolving and mixing 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and vinyltriethoxysilane, adding a catalyst for reaction, then adding magnesium hydroxide, drying a product after the reaction to obtain DOPO coated modified magnesium hydroxide, dissolving ethyl cellulose, adding DOPO coated modified magnesium hydroxide, 2,4 toluene diisocyanate, a dispersing agent and the catalyst, and drying the product after the reaction. The invention enhances the compatibility with a polymer matrix through double-layer coating modification, delays the reduction of the tensile property of the composite material, and effectively improves the flame retardant property of the material.

Inventors

  • XIE AN
  • Ning Dianfan
  • TANG XIAOQIANG

Assignees

  • 扬州大学

Dates

Publication Date
20260512
Application Date
20260313

Claims (10)

  1. 1. The double-shell microcapsule modified magnesium hydroxide flame retardant is characterized in that magnesium hydroxide is taken as a core, and the core is sequentially coated with an inner wall formed by 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and an outer wall formed by ethylcellulose.
  2. 2. A method for preparing the double-shell microcapsule modified magnesium hydroxide flame retardant according to claim 1, which is characterized by comprising the following steps: (1) Respectively dissolving 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and vinyl triethoxysilane in absolute ethyl alcohol, mixing, and adding a catalyst for reaction; (2) Adding magnesium hydroxide into a reaction system, washing, filtering and drying after the reaction is finished to obtain DOPO coated modified magnesium hydroxide; (3) Dissolving ethyl cellulose in ethyl acetate, adding DOPO coated modified magnesium hydroxide, 2,4 toluene diisocyanate, a dispersing agent and a catalyst, washing, filtering and drying after the reaction is completed, and obtaining the double-shell microcapsule modified magnesium hydroxide flame retardant.
  3. 3. The preparation method of the double-shell microcapsule modified magnesium hydroxide flame retardant according to claim 2, wherein in the step (1), the catalyst is azodiisobutyronitrile, the amount of the azodiisobutyronitrile is 1-2% of the mass of the system, the reaction temperature is 70-90 ℃, and the reaction time is 10-12 hours.
  4. 4. The method for preparing the double-shell microcapsule modified magnesium hydroxide flame retardant according to claim 2, wherein in the step (2), the reaction temperature is 70-90 ℃ and the reaction time is 6-8 hours.
  5. 5. The preparation method of the double-shell microcapsule modified magnesium hydroxide flame retardant according to claim 2, wherein in the step (3), the catalyst is dibutyl tin dilaurate, the dosage of the dibutyl tin dilaurate is 0.1-0.2% of the mass of the system, the dispersing agent is polyoxyethylene octyl phenol ether-10, the dosage of the polyoxyethylene octyl phenol ether-10 is 0.1-0.2% of the mass of the system, the reaction temperature is 70-90 ℃, and the reaction time is 6-8 hours.
  6. 6. The preparation method of the double-shell microcapsule modified magnesium hydroxide flame retardant according to claim 2, wherein the drying temperature in the step (2) is 50-80 ℃ for 36-48 hours, and the drying temperature in the step (3) is 50-80 ℃ for 36-48 hours.
  7. 7. Use of the double shell microcapsule modified magnesium hydroxide flame retardant according to claim 1 in flame retardant materials.
  8. 8. The application of claim 7, wherein the double-shell microcapsule modified magnesium hydroxide flame retardant is added into the epoxy resin, the curing agent is added after stirring, stirring is carried out again, the mixture is poured into a mold, heating and curing are carried out, and the epoxy resin flame retardant material containing the double-shell microcapsule modified magnesium hydroxide flame retardant is obtained, wherein the curing temperature is 80-160 ℃, and the curing time is 2-6 hours.
  9. 9. The application of claim 7, wherein the double-shell microcapsule modified magnesium hydroxide flame retardant is added into the unsaturated polyester resin, the curing agent is added after stirring, the stirring is performed again, the mixture is poured into a mold, and the heating and the curing are performed to obtain the unsaturated polyester resin flame retardant material containing the double-shell microcapsule modified magnesium hydroxide flame retardant, wherein the curing temperature is 80-120 ℃, and the curing time is 1-4 hours.
  10. 10. The application of claim 7, wherein the double-shell microcapsule modified magnesium hydroxide flame retardant is added into the ethylene-vinyl acetate copolymer, the ethylene-vinyl acetate copolymer material filled with the flame retardant is subjected to hot pressing and then is subjected to sheet discharging, and the ethylene-vinyl acetate copolymer flame retardant material containing the double-shell microcapsule modified magnesium hydroxide flame retardant is obtained, wherein the hot pressing temperature is 100-120 ℃, and the hot pressing time is 10-20 minutes.

Description

Double-shell microcapsule modified magnesium hydroxide flame retardant and preparation method and application thereof Technical Field The invention relates to a flame retardant and a preparation method and application thereof, in particular to a double-shell microcapsule modified magnesium hydroxide flame retardant and a preparation method and application thereof. Background In many fire scenes, polymer materials are a non-negligible source of risk due to their widespread use. Most of the polymer materials have inflammability, and the polymer materials spread rapidly during combustion, release a large amount of heat and toxic smoke, and obviously increase fire hazard. Therefore, flame retardant treatment of the polymer material has very important practical significance to the current society. Magnesium Hydroxide (MH) is a typical inorganic flame retardant, and is attracting attention because of its good smoke suppression effect, no generation of toxic gas, wide raw material source, and low cost. However, MH has obvious defects in practical application that the surface polarity is strong, the hydrophilic and oleophobic characteristics are presented, the dispersibility in a polymer matrix is poor, the polymer matrix is easy to agglomerate, meanwhile, the flame retardant efficiency is limited, the flame retardance of the polymer material can be effectively improved only by high addition, and the mechanical properties of the material are seriously damaged by the excessive addition, so that the application of the polymer material is limited. Therefore, it is an important research direction to modify MH to improve its compatibility with the matrix, dispersibility and flame retardant efficiency. In practical application, a single flame retardant often has difficulty in comprehensively meeting the comprehensive requirements of materials on flame retardant property and mechanical property. The efficient flame retardance is realized by compounding flame retardants with different flame retarding mechanisms and utilizing a synergistic effect, so that the flame retardance has become an important development trend. However, magnesium hydroxide has poor dispersibility in a polymer matrix and is easy to agglomerate, so that stress concentration points appear in the material, the mechanical property of the material is reduced, and the relative content of magnesium hydroxide in a composite system is reduced by coating the surface of the magnesium hydroxide with the microcapsule, so that the flame retardant effect of the magnesium hydroxide in the material is weakened. In addition, most microcapsule coating layers in the magnesium hydroxide coating modification have no flame retardant function, and even the flame retardant effect of the magnesium hydroxide can be diluted. The microcapsule coating on the surface of magnesium hydroxide can lead to the decrease of the flame retardant property of the magnesium hydroxide. Disclosure of Invention The invention aims to provide the double-shell microcapsule modified magnesium hydroxide flame retardant which can enhance the compatibility with a polymer matrix, delay the reduction of the tensile property of a composite material and has high flame retardant efficiency; the second object of the invention is to provide a preparation method of the double-shell microcapsule modified magnesium hydroxide flame retardant, and the third object of the invention is to provide an application of the double-shell microcapsule modified magnesium hydroxide flame retardant. According to the technical scheme, the double-shell microcapsule modified magnesium hydroxide flame retardant takes magnesium hydroxide as a core, and the core is sequentially coated with an inner wall formed by 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and an outer wall formed by ethyl cellulose. The preparation method of the double-shell microcapsule modified magnesium hydroxide flame retardant comprises the following steps: (1) Respectively dissolving 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and vinyl triethoxysilane in absolute ethyl alcohol, mixing, and adding a catalyst for reaction; (2) Adding magnesium hydroxide into a reaction system, washing, filtering and drying after the reaction is finished to obtain DOPO coated modified magnesium hydroxide; (3) Dissolving ethyl cellulose in ethyl acetate, adding DOPO coated modified magnesium hydroxide, 2,4 toluene diisocyanate, a dispersing agent and a catalyst, washing, filtering and drying after the reaction is completed, and obtaining the double-shell microcapsule modified magnesium hydroxide flame retardant. In the step (1), the catalyst is azobisisobutyronitrile, the dosage of the azobisisobutyronitrile is 1-2% of the mass of the system, the reaction temperature is 70-90 ℃, and the reaction time is 10-12 hours. Preferably, the amount of the azodiisobutyronitrile is 1% of the mass of the system, and the reaction temperature is 75 ℃. In the step (2), the reacti