阅读说明：本技术 具有自由基猝灭功能单组份膨胀型阻燃剂及其制备方法与应用 (Single-component intumescent flame retardant with free radical quenching function and preparation method and application thereof ) 是由 赖学军 曾运生 李佳欣 曾幸荣 李红强 江昌乘 陈宇轩 于 2019-10-12 设计创作，主要内容包括：本发明公开了具有自由基猝灭功能单组份膨胀型阻燃剂及其制备方法与应用。该制备方法以三聚氯氰、烷氧基硅烷、受阻胺单体和二胺单体为原料,先后在0～25℃和45～65℃下反应得到中间产物。随后在80～120℃条件下,将中间产物、氮磷阻燃剂和二胺单体通过离子交换及亲核取代反应,制备具有自由基猝灭功能的单组份膨胀型阻燃剂,并将其应用于聚丙烯阻燃。与现有技术相比,本发明所制备的单组份膨胀型阻燃剂,易于控制磷、氮元素的比例,有利于自由基猝灭与膨胀成炭过程的高效耦合、阻燃效率高,只需添加少量即可发挥高效的阻燃作用,并具有突出的耐水性能,广泛应用于电子电器、建筑装饰和汽车配件等领域。(The invention discloses a single-component intumescent flame retardant with a free radical quenching function, and a preparation method and application thereof. The preparation method comprises the steps of taking cyanuric chloride, alkoxy silane, hindered amine monomer and diamine monomer as raw materials, and reacting at 0-25 ℃ and 45-65 ℃ in sequence to obtain an intermediate product. And then, carrying out ion exchange and nucleophilic substitution reaction on the intermediate product, the nitrogen-phosphorus flame retardant and the diamine monomer at the temperature of 80-120 ℃ to prepare the single-component intumescent flame retardant with the free radical quenching function, and applying the single-component intumescent flame retardant to polypropylene flame retardance. Compared with the prior art, the single-component intumescent flame retardant prepared by the invention is easy to control the proportion of phosphorus and nitrogen elements, is beneficial to efficient coupling of free radical quenching and an intumescent carbonization process, has high flame retardant efficiency, can play an efficient flame retardant role only by adding a small amount of flame retardant, has outstanding water resistance, and is widely applied to the fields of electronic appliances, architectural decoration, automobile accessories and the like.)

1. The preparation method of the single-component intumescent flame retardant with the free radical quenching function is characterized by comprising the following steps:

1) preparation of macromolecular char-forming agent containing hindered amine structure

Adding an organic solvent and cyanuric chloride into a reaction kettle at the temperature of 0-25 ℃, and uniformly stirring; adding alkoxy silane and hindered amine monomer, dropwise adding an acid-binding agent, and reacting for 1-6 h; then heating to 45-65 ℃, dropwise adding a mixed aqueous solution of a diamine monomer and an acid-binding agent, and continuously reacting for 1-6 h; after the reaction is finished, filtering, washing and vacuum drying the solution to obtain a hindered amine structure-containing macromolecular charring agent; the molar ratio of the cyanuric chloride to the alkoxy silane is 1: 0.5-1: 2; the molar ratio of the cyanuric chloride to the hindered amine monomer is 1: 0.001-1: 0.1;

2) preparation of single-component intumescent flame retardant with free radical quenching function

Mixing an organic solvent, a hindered amine structure-containing macromolecular char-forming agent and a nitrogen-phosphorus flame retardant at 80-120 ℃, adding a mixed aqueous solution of a diamine monomer and an acid-binding agent, and continuing to react for 5-10 hours; and after the reaction is finished, filtering, washing and vacuum drying the mixed solution to obtain the single-component intumescent flame retardant with the free radical quenching function.

2. The method for preparing the single-component intumescent flame retardant with the free radical quenching function as claimed in claim 1, characterized in that the alkoxy silane is one or more of 3-aminopropyl trimethoxy silane, 3-aminopropyl triethoxy silane and gamma-aminopropyl methyl diethoxy silane.

3. A process for preparing a mono-component intumescent flame retardant with a radical quenching function as claimed in claim 1, characterized in that said hindered amine monomer is one or more of 2, 4-bis- [ N-butyl-N- (1-cyclohexyloxy-2, 2,6, 6-tetramethyl-4-piperidyl) amino ] -6- (2-hydroxyethylamino) -1,3, 5-triazine, 4-hydroxy-2, 2,6, 6-tetramethyl-1- (1-phenylethoxy) piperidine, tetramethylpiperidylamine.

The structural formula of the 2, 4-bis- [ N-N-butyl-N- (1-cyclohexyloxy-2, 2,6, 6-tetramethyl-4-piperidyl) amino ] -6- (2-hydroxyethylamino) -1,3, 5-triazine is as follows:

the structural formula of the 4-hydroxy-2, 2,6, 6-tetramethyl-1- (1-phenylethoxy) piperidine is as follows:

the structural formula of the tetramethylpiperidine amine is as follows:

4. the process for preparing the single-component intumescent flame retardant with the free radical quenching function according to claim 1, wherein in the step 1) and the step 2), the organic solvent is one or more of acetonitrile, acetone, 1, 4-dioxane, cyclohexane and toluene.

5. The preparation method of the single-component intumescent flame retardant with the free radical quenching function according to claim 1, characterized in that the nitrogen and phosphorus flame retardant is one or more of ammonium polyphosphate, melamine pyrophosphate and ammonium dihydrogen phosphate; the mass ratio of the hindered amine structure-containing macromolecular charring agent to the nitrogen-phosphorus flame retardant is 1: 0.5-1: 4.

6. The preparation method of the single-component intumescent flame retardant with the free radical quenching function according to claim 1, wherein the acid-binding agent is one or more of sodium acetate, potassium carbonate, sodium hydroxide, triethylamine and N, N-diisopropylethylamine, and pyridine, and the molar ratio of the amount of the acid-binding agent added each time to the cyanuric chloride is 3: 1-1: 1.

7. The method for preparing the single-component intumescent flame retardant with the free radical quenching function according to claim 1, characterized in that the diamine monomer is one or more of ethylenediamine, phenylenediamine, tris (4-aminophenyl) amine and N, N-bis (3-aminopropyl) methylamine; the molar ratio of cyanuric chloride to diamine monomer added each time is 4: 1-1: 2.

8. The preparation method of the single-component intumescent flame retardant with the free radical quenching function according to claim 1, characterized in that in the step 1), the dropwise addition of the mixed aqueous solution of the diamine monomer and the acid-binding agent is completed within 1-3 h; the stirring is uniformly carried out for 30-40 min; the alkoxy silane and hindered amine monomer are added by respectively dissolving the alkoxy silane and hindered amine monomer in an organic solvent and adding within 1-4 h;

in the step 2), the addition of the mixed aqueous solution of the diamine monomer and the acid-binding agent is completed within 1-3 h.

9. A single-component intumescent flame retardant with a free radical quenching function, characterized in that the flame retardant is prepared by the preparation method of any one of claims 1 to 8; the particle size of the flame retardant is 1-40 μm.

10. The use of the single-component intumescent flame retardant with a free radical quenching function in polypropylene according to claim 9 is characterized in that: adding the polypropylene granules to an open type rubber mixing mill with a double-roller temperature of 170-185 ℃, melting and roll wrapping, adding 20-30 parts by mass of single-component intumescent flame retardant with a free radical quenching function, mixing for 10-15 min, then hot-pressing for 5-10 min in a flat vulcanizing machine at 180-190 ℃, finally cold-pressing for 5-15 min at room temperature in a cold press, and discharging to obtain the flame-retardant polypropylene material with excellent flame retardant property and water resistance.

Technical Field

The invention relates to the field of preparation and application of a polymer halogen-free flame retardant, in particular to a single-component intumescent flame retardant with a free radical quenching function, and a preparation method and application thereof.

Background

Polypropylene (PP) is easy to crack at high temperature to generate R & H & lt- & gt, or is oxidized to generate RO & HO & lt- & gt, the free radicals can further promote the chain degradation of PP, release a large amount of combustible gases such as small-molecular alkanes, olefins, ketones and aldehydes, and the like, and after being mixed with oxygen, the mixture can be violently combusted when meeting open fire and release a large amount of heat, so that the degradation and combustion of PP are further promoted.

Hindered amines have excellent radical trapping function, are often used as light stabilizers in the fields of polyolefin films, polymer coatings and the like, and have recently been found to exert good flame retardant action in polymers. Xie et al take 2,2,6, 6-tetramethyl piperidine amine, phenylphosphonic dichloride and the like as raw materials, synthesize a macromolecular intumescent flame retardant (HAPN) containing hindered amine groups through nucleophilic substitution reaction, and compound the flame retardant with ammonium polyphosphate (APP) to form flame retardant polypropylene (Synthesis of a novel macromolecular crosslinking agent with free-radial crosslinking reactivity and tissue in a flame retardant polypropylene [ J ]. Polymer Degradation and stability,2016,130:68-77), and the nitroxide radical generated by the action of the hindered amine by the action of thermal oxygen can capture the active radical cracked by the polypropylene in gas phase and condensed phase, thereby delaying the chain Degradation reaction of the polypropylene. However, too high a hindered amine content promotes the degradation of PP, accelerating the combustion of the polymer. The HAPN has the advantages that the hindered amine structure and the carbon source structure are on the same molecule, so that the proportion of the hindered amine structure and the carbon source structure is difficult to regulate, and the flame retardant efficiency is influenced. The fire retardant can greatly improve the fire retardant performance and the light stability of the polymer and obviously improve the quality and the structure of a carbon layer, but because the fire retardant is used for PP fire retardation with the traditional intumescent fire retardant (ammonium polyphosphate/pentaerythritol/melamine) only through simple mechanical mixing, the uniform dispersion reaction of each component is difficult to ensure, and the situation that the content of a certain component in a local area is too high or too low can occur. In addition, the traditional intumescent flame retardant has large polarity and poor water resistance, more parts are added, and the flame retardant efficiency is low, so that the further popularization and application of the traditional intumescent flame retardant are greatly limited.

Chinese patent 2016107726988 discloses an aryl POSS flame retardant with a free radical quenching function, and a synthesis method and application thereof. In the synthesis method, aryl siloxane is subjected to hydrolytic condensation under the action of inorganic alkali and water to prepare aryl cage-shaped silsesquioxane triol alkali metal salt; and then reacting the alkali metal salt with alkenyl silane under the action of a tertiary amine catalyst at 0-25 ℃ to obtain the reactive aryl polysilsesquioxane flame retardant with the free radical quenching function. The prepared flame retardant has the advantages of excellent thermal stability and char formation, good compatibility with silicon rubber and the like. The flame-retardant silicone rubber material with excellent mechanical property, thermal stability and flame retardance can be prepared by only adding a small amount of POSS flame retardant into silicone rubber. The silicon rubber is a semi-inorganic high-molecular elastomer with a main chain of Si-O-Si bonds and side chains of organic groups (such as phenyl, methyl, vinyl and the like), has good thermal stability, small smoke generation amount, no toxicity and high-temperature charring property, namely, a large amount of ceramic residues (mainly containing silicon, oxygen, carbon and other inorganic elements) can be formed under the high-temperature condition, and can play a flame-retardant role in blocking heat transmission. However, the combustion reaction of polypropylene is carried out by free radical chain scission degradation, which is not easy to form carbon and has low carbon residue rate, and the aryl POSS is difficult to play an ideal role in flame-retardant polypropylene.

Disclosure of Invention

The invention aims to provide a single-component intumescent flame retardant with a free radical quenching function aiming at the defects of the existing intumescent flame retardant, and the flame retardant can effectively overcome the defects that the existing multicomponent intumescent flame retardant has high hygroscopicity and poor compatibility with a matrix, is easy to migrate to the surface of a polymer and lose; and meanwhile, the free radical quenching function is endowed, so that the free radical quenching function is efficiently coupled with the expansion carbonization process, and the efficient flame-retardant effect is exerted.

The invention also aims to provide a preparation method of the single-component intumescent flame retardant with the free radical quenching function.

It is also an object of the present invention to provide the use of a one-component intumescent flame retardant having a radical quenching function.

According to the invention, through molecular design, the hindered amine-containing macromolecular charring agent is hybridized with the nitrogen-phosphorus intumescent flame retardant to prepare the single-component intumescent flame retardant which has excellent flame retardant property, water resistance and good compatibility with a substrate and has a free radical quenching function, and the requirements of people on the multifunctional flame retardant can be met.

The purpose of the invention can be realized by the following technical scheme:

a preparation method of a single-component intumescent flame retardant with a free radical quenching function comprises the following steps:

(1) preparation of macromolecular char-forming agent containing hindered amine structure

Adding an organic solvent and cyanuric chloride into a reaction kettle at the temperature of 0-25 ℃, and stirring for 30-40 min to uniformly disperse the cyanuric chloride; respectively dissolving alkoxy silane and hindered amine monomers in an organic solvent, slowly adding the mixture into a reaction kettle within 1-4 h, simultaneously dropwise adding an acid-binding agent, and reacting for 1-6 h after dropwise adding is finished; then heating to 45-65 ℃, slowly dripping a mixed aqueous solution of diamine monomers and an acid-binding agent within 1-3 h, and continuously reacting for 1-6 h after dripping; and after the reaction is finished, filtering, washing and vacuum drying the solution to obtain the hindered amine structure-containing macromolecular charring agent.

(2) Preparation of single-component intumescent flame retardant with free radical quenching function

Adding an organic solvent, a hindered amine structure-containing macromolecular char-forming agent and a nitrogen-phosphorus flame retardant into a flask at the temperature of 80-120 ℃, adding a mixed aqueous solution of a diamine monomer and an acid-binding agent within 1-3 h, and continuing to react for 5-10 h after the dropwise addition is finished; and after the reaction is finished, filtering, washing and vacuum drying the mixed solution to obtain the single-component intumescent flame retardant with the free radical quenching function.

To further achieve the object of the present invention, preferably, the alkoxysilane is one or more of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, γ -aminopropylmethyldiethoxysilane. The molar ratio of the cyanuric chloride to the alkoxy silane is 1: 0.5-1: 2.

Preferably, the hindered amine monomer is one or more of 2, 4-bis- [ N-butyl-N- (1-cyclohexyloxy-2, 2,6, 6-tetramethyl-4-piperidyl) amino ] -6- (2-hydroxyethylamino) -1,3, 5-triazine, 4-hydroxy-2, 2,6, 6-tetramethyl-1- (1-phenylethoxy) piperidine or tetramethylpiperidylamine.

The structural formula of the 2, 4-bis- [ N-N-butyl-N- (1-cyclohexyloxy-2, 2,6, 6-tetramethyl-4-piperidyl) amino ] -6- (2-hydroxyethylamino) -1,3, 5-triazine is as follows:

the structural formula of the 4-hydroxy-2, 2,6, 6-tetramethyl-1- (1-phenylethoxy) piperidine is as follows:

the structural formula of the tetramethylpiperidine amine is as follows:

preferably, the organic solvent is one or more of acetonitrile, acetone, 1, 4-dioxane, cyclohexane and toluene.

Preferably, the nitrogen-phosphorus flame retardant is one or more of ammonium polyphosphate, melamine pyrophosphate and ammonium dihydrogen phosphate. The mass ratio of the hindered amine structure-containing macromolecular charring agent to the nitrogen-phosphorus flame retardant is 1: 0.5-1: 4.

Preferably, the molar ratio of the cyanuric chloride to the hindered amine monomer is 1: 0.001-1: 0.1.

Preferably, the acid-binding agent is one or more of sodium acetate, potassium carbonate, sodium hydroxide, triethylamine, N-diisopropylethylamine and pyridine, and the molar ratio of the amount of the acid-binding agent added to the cyanuric chloride each time is 3: 1-1: 1.

Preferably, the diamine monomer is one or more of ethylenediamine, phenylenediamine, tris (4-aminophenyl) amine and N, N-bis (3-aminopropyl) methylamine, and the molar ratio of cyanuric chloride to the diamine monomer added each time is 4: 1-1: 2.

A single-component intumescent flame retardant with a free radical quenching function is prepared by the preparation method; the particle size of the flame retardant is 1-40 μm.

The application of the single-component intumescent flame retardant with the free radical quenching function in polypropylene comprises the following steps: adding the polypropylene granules to an open type rubber mixing mill with a double-roller temperature of 170-185 ℃, after the polypropylene granules are melted and wrapped, adding 20-30 parts by mass of a single-component intumescent flame retardant with a free radical quenching function, mixing for 10-15 min, then hot-pressing for 5-10 min in a flat vulcanizing machine at 180-190 ℃, finally cold-pressing for 5-15 min at room temperature in a cold press, and discharging to obtain the flame-retardant polypropylene material with excellent flame retardant performance and water resistance.

The flame retardant mechanism of the single-component intumescent flame retardant with the free radical quenching function is mainly condensed phase and gas phase flame retardant. The macromolecule carbon forming agent and acid source ammonium polyphosphate generate esterification, crosslinking and carbonization reactions, and meanwhile, the generated nitrogen, ammonia gas and other non-combustible gases expand the carbon layer and block heat, combustible gas and oxygen; meanwhile, the nitroxide free radical decomposed by the hindered amine and the macromolecular active free radical generated by the PP are trapped in the micro-nano confinement space of the carbon layer, the nitroxide free radical can efficiently quench the macromolecular active free radical to generate a compound with lower reactivity, and the chain reaction of PP cracking free radicals is blocked, so that the fire is delayed and even stopped.

Compared with the prior art, the invention has the following advantages:

1. the single-component intumescent flame retardant with the free radical quenching function, which is prepared by the invention, has the functions of catalytic char formation and intumescent char formation, and the ratio of the hindered amine, the nitrogen-phosphorus flame retardant and the char former is effectively controlled by regulating and controlling the feed ratio of the raw materials, so that the free radical quenching function of the hindered amine and the intumescent char formation of the intumescent flame retardant are efficiently coupled, and the efficient flame retardant effect is exerted.

2. According to the single-component intumescent flame retardant with the free radical quenching function, the organic char forming agent and the inorganic nitrogen and phosphorus intumescent flame retardant are hybridized, so that the dispersibility of the nitrogen and phosphorus intumescent flame retardant in a polymer matrix can be improved, and meanwhile, the char forming agent and the nitrogen and phosphorus flame retardant are subjected to close contact reaction, so that the flame retardant efficiency is improved.

3. The single-component intumescent flame retardant with the free radical quenching function, which is prepared by the invention, selects the silicon-containing char forming agent with high flame retardant efficiency, can generate compact and firm char layer wrapping molten drops in time, and prevents the molten drops from falling to other places to form a new ignition point.

4. According to the single-component intumescent flame retardant with the free radical quenching function, the silicon-containing macromolecular charring agent is used for replacing a carbon source, namely Pentaerythritol (PER), in the traditional intumescent flame retardant, so that the compatibility of the flame retardant and a matrix is improved, and the water resistance of the nitrogen-phosphorus flame retardant can be effectively improved by hybridization of the silicon-containing charring agent and the nitrogen-phosphorus flame retardant.

5. The combustion mechanisms of polypropylene and silicon rubber are different, and the flame retardant can play a role in high-efficiency flame retardance in polypropylene by realizing the high-efficiency coupling of the free radical quenching function of hindered amine and the expansion carbon forming function of the intumescent flame retardant.

Drawings

FIG. 1 is a graph of water contact angle for unmodified ammonium polyphosphate;

FIG. 2 is a graph of the water contact angle of the product obtained in example 1;

FIG. 3 is a Scanning Electron Microscope (SEM) image of unmodified ammonium polyphosphate;

FIG. 4 is a Scanning Electron Microscope (SEM) image of the product obtained in example 1;

FIG. 5 is a Fourier transform infrared spectroscopy (FTIR) plot of example 1 with unmodified ammonium polyphosphate.

Detailed Description

For a better understanding of the present invention, the present invention will be further described with reference to the accompanying drawings and examples, but the embodiments of the present invention are not limited thereto.