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CN-121991546-A - Core-shell structure composite flame-retardant synergist and preparation method and application thereof, intumescent fireproof coating and preparation and application thereof

CN121991546ACN 121991546 ACN121991546 ACN 121991546ACN-121991546-A

Abstract

The invention provides a core-shell structure composite flame-retardant synergist, a preparation method and application thereof, an intumescent fire-retardant coating, and a preparation and application thereof, and belongs to the technical field of fire-fighting materials. According to the invention, the ammonium polyphosphate APP and melamine MEL which are independently existing in the prior art are subjected to molecular-level compounding and assembly on the surface of zinc borate particles serving as anchor points by a coprecipitation method, so that the core-shell integrated functional particles are formed. Under the high temperature of fire, APP and MEL of the outer shell layer are in close contact, so that the reaction path is extremely short, severe dehydration, gasification and crosslinking reactions can be instantaneously generated, a strong expansion driving force with more controllable directivity is generated, the expansion efficiency is greatly improved, and the coating fire resistance, the carbon layer quality and the durability of the fireproof coating can be remarkably improved.

Inventors

  • YANG LIANG
  • ZHANG LICHEN
  • BAI BIN
  • ZHAO JING

Assignees

  • 应急管理部天津消防研究所

Dates

Publication Date
20260508
Application Date
20260324

Claims (10)

  1. 1. The preparation method of the core-shell structure composite flame-retardant synergist is characterized by comprising the following steps of: Dispersing zinc borate in water to obtain zinc borate suspension; mixing ammonium polyphosphate and melamine with water to obtain ammonium polyphosphate-melamine mixed solution; And regulating the pH value of the zinc borate suspension to 4.0-5.0, adding the ammonium polyphosphate-melamine mixed solution, and performing curing reaction to obtain the core-shell structure composite flame retardant synergist.
  2. 2. The preparation method according to claim 1, wherein the dispersing temperature is 50-70 ℃, the rotating speed is 500-1000 r/min, the time is 15-30 min, and the solid content of the zinc borate suspension is 10-20wt%.
  3. 3. The preparation method of the ammonium polyphosphate-melamine composite solution is characterized in that the mass ratio of the ammonium polyphosphate to the melamine is 1.5-2.5:1, the mass ratio of the total mass of the ammonium polyphosphate and the melamine to the zinc borate is 1.8-3:1, and the total mass concentration of the ammonium polyphosphate-melamine composite solution is 15-25%.
  4. 4. The preparation method of claim 1, wherein the pH value is adjusted by dilute hydrochloric acid or acetic acid, and the curing reaction is carried out at 50-70 ℃ for 90-150 min.
  5. 5. The core-shell structure composite flame retardant synergist prepared by the preparation method of any one of claims 1-4.
  6. 6. The use of the core-shell structured composite flame retardant synergist of claim 5 in intumescent fire retardant coatings.
  7. 7. The intumescent fire-retardant coating based on the core-shell structure composite flame-retardant synergist comprises the following preparation raw materials in percentage by mass: 25-35% of film forming matrix, 8-15% of carbon source, 17-30% of composite flame retardant synergist, 8-15% of char formation promoter, 15-20% of reinforcing filler, 2-5% of auxiliary agent and the balance of water; The composite flame-retardant synergist is the core-shell structure composite flame-retardant synergist of claim 5; The auxiliary agent comprises wetting dispersant, defoamer, leveling agent, thickener and anti-settling agent.
  8. 8. The intumescent fire retardant coating of claim 7 wherein said film-forming matrix comprises one or more of an aqueous epoxy emulsion, an aqueous acrylic emulsion, a styrene-acrylic emulsion; the carbon source comprises one or more of pentaerythritol, dipentaerythritol, starch and sorbitol; The carbon forming accelerant comprises one or more of melamine, dicyandiamide, melamine polyphosphate and expandable graphite; The reinforcing filler comprises one or more of titanium dioxide, aluminum hydroxide, magnesium hydroxide, silica micropowder and sepiolite fiber.
  9. 9. The method for preparing the intumescent fire retardant coating as claimed in any one of claims 7-8, characterized by comprising the following steps: Firstly mixing water, a wetting dispersant, a defoaming agent, a carbon source, a char formation promoter and a reinforcing filler to obtain slurry; performing secondary mixing on the slurry and the composite flame retardant synergist to obtain a mixture; And mixing the mixture with a film-forming matrix, adding a leveling agent, a thickening agent and an anti-settling agent, and curing to obtain the intumescent fire-retardant coating.
  10. 10. The application of the intumescent coating of any one of claims 7-8 or the intumescent coating prepared by the preparation method of claim 9 in the field of steel structure protection.

Description

Core-shell structure composite flame-retardant synergist and preparation method and application thereof, intumescent fireproof coating and preparation and application thereof Technical Field The invention relates to the technical field of fire-fighting materials, in particular to a core-shell structure composite flame-retardant synergist, a preparation method and application thereof, an intumescent fire-retardant coating and a preparation and application thereof. Background The steel structure is a core bearing structure of modern buildings, bridges and industrial facilities, but has poor fire resistance, and can rapidly lose bearing capacity under the action of high temperature in fire, thereby causing structural collapse. The intumescent fire retardant coating is the most widely used fire protection means for steel structures at present. The mechanism of action is that under the action of flame or high temperature, each component is subjected to complex physical and chemical change, and is rapidly expanded and foamed to form the porous carbon heat insulation layer with the thickness of tens to hundreds of times, so that the heat transfer to the steel substrate is effectively delayed, and valuable time is gained for personnel evacuation and fire rescue. Conventional intumescent coatings are typically composed of three basic components, an acid source (e.g., ammonium polyphosphate, APP), a carbon source (e.g., pentaerythritol, PER) and a gas source (e.g., melamine, MEL), and a film-forming matrix (e.g., epoxy, acrylic emulsion, etc.) that adheres these components to the steel surface. Although this system is well established, its inherent drawbacks limit further performance improvements. The traditional process is to take APP, PER, MEL and other components as independent powder for simple physical blending. During high-temperature reaction, the dispersed particles need to be in contact with each other and react through thermal diffusion, the reaction efficiency is low, and the expansion is insufficient and inconsistent easily caused by uneven heating. Secondly, the carbon layer formed by the physical mixed system is loose, low in strength and easy to crack, and is easy to pulverize and fall off under the action of high-temperature flame scouring or thermal shock, so that the heat insulation barrier is invalid. To improve the properties, additives such as zinc borate, expandable graphite, etc. are often added as synergists. However, conventional physical addition means provide these synergists in a punctiform isolated distribution in the coating, lack of a close physicochemical link with the APP/MEL/PER host expansion system, have limited synergy, and may affect the mechanical properties of the coating. In the prior art, modification of a single component has been studied, but the coating of APP has been focused on a large number of cases. The prior art (willow, shen Jian, luo Wensheng, li Xinyo, wang Mingzhi. MFAPP for preparing flame-retardant impregnated paper and its application in veneered high density fiberboard [ J ]. Peking university of forestry, 2023, 45 (12): 134-148.) adopts melamine formaldehyde resin to coat APP for preparing microencapsulated APP, or optimizes carbon. Although these methods can improve moisture absorption or increase carbon residue to some extent, they have failed to essentially solve the problem of "in situ" high-efficiency synergy of acid source, carbon source, and gas source at high temperatures. Therefore, there is a need to provide a novel high-performance intumescent fire-retardant coating, which overcomes the defects of low reaction efficiency, poor cooperativity, poor carbon layer quality and the like caused by multi-component physical mixing of the existing intumescent fire-retardant coating. Disclosure of Invention The invention aims to provide a core-shell structure composite flame-retardant synergist, a preparation method and application thereof, an intumescent fire-retardant coating, and a preparation method and application thereof, which can solve the defects of low reaction efficiency, poor cooperativity, poor carbon layer quality and the like caused by simple physical mixing of components of the conventional intumescent fire-retardant coating. In order to achieve the above object, the present invention provides the following technical solutions: the invention provides a preparation method of a core-shell structure composite flame-retardant synergist, which comprises the following steps: Dispersing zinc borate in water to obtain zinc borate suspension; mixing ammonium polyphosphate and melamine with water to obtain ammonium polyphosphate-melamine mixed solution; And regulating the pH value of the zinc borate suspension to 4.0-5.0, adding the ammonium polyphosphate-melamine mixed solution, and performing curing reaction to obtain the core-shell structure composite flame retardant synergist. Preferably, the dispersing temperature is 50-70 ℃, the rotating speed is