阅读说明：本技术 一种基于磷腈的有机金属配合物阻燃环氧树脂及其制备方法 (Phosphazene-based organic metal complex flame-retardant epoxy resin and preparation method thereof ) 是由 许博 刘艳婷 许准 毕晓露 钱立军 汪玲 于 2020-05-09 设计创作，主要内容包括：本发明涉及一种基于磷腈的有机金属配合物阻燃环氧树脂及其制备方法,属于在普通环氧树脂中添加特定阻燃成分获得阻燃环氧树脂材料的技术领域。本发明以环三磷腈氮杂环类配体构筑的有机金属配合物独立作为阻燃剂与双酚A二缩水甘油醚环氧树脂在一定温度下进行熔融共混,制得阻燃环氧树脂,再向阻燃环氧树脂中加入固化剂,在一定温度下完成环氧树脂的固化反应,获得阻燃性能优异的环氧树脂固化物。本发明制得的阻燃环氧树脂阻燃效率高,碳层致密,燃烧过程中低烟低毒害,具有良好的应用前景。(The invention relates to an organic metal complex flame-retardant epoxy resin based on phosphazene and a preparation method thereof, belonging to the technical field of obtaining flame-retardant epoxy resin materials by adding specific flame-retardant components into common epoxy resin. According to the invention, an organic metal complex constructed by a cyclotriphosphazene nitrogen heterocyclic ligand is independently used as a flame retardant to be fused and blended with bisphenol A diglycidyl ether epoxy resin at a certain temperature to prepare flame-retardant epoxy resin, then a curing agent is added into the flame-retardant epoxy resin, and the curing reaction of the epoxy resin is completed at a certain temperature to obtain an epoxy resin cured product with excellent flame-retardant property. The flame-retardant epoxy resin prepared by the invention has high flame-retardant efficiency, compact carbon layer, low smoke and low toxicity in the combustion process and good application prospect.)

1. A preparation method of phosphazene-based organic metal complex flame-retardant epoxy resin is characterized by comprising the following steps:

(1) heating bisphenol A diglycidyl ether epoxy resin, adding an organic metal complex constructed based on a cyclotriphosphazene nitrogen heterocyclic ligand into the epoxy resin, and continuously stirring;

(2) and (3) cooling the treated epoxy resin, adding a curing agent with equivalent weight to epoxy groups in the epoxy resin under the stirring condition, stirring until the curing agent is fully dissolved or dispersed, removing air in a mixed system under the vacuum condition, heating and curing to obtain the phosphazene-based organic metal complex flame-retardant epoxy resin material.

2. The method for preparing a phosphazene-based organic metal complex flame-retardant epoxy resin according to claim 1, wherein the chemical structure of the organic metal complex constructed based on cyclotriphosphazene azaheterocyclic ligand in the step (1) is as follows:

the wavy line indicates that the compound molecule has a plurality of repeating structures as described above.

3. The method for preparing a phosphazene-based organometallic complex flame-retardant epoxy resin according to claim 1, wherein the epoxy value of the bisphenol a diglycidyl ether epoxy resin used is in a range of 0.10 to 0.54; the adopted curing agent is one of 4,4 '-diaminodiphenyl sulfone, 4' -diaminodiphenyl methane, dicyanodiamide, m-phenylenediamine, linear phenolic resin and m-xylylenediamine.

4. The method for preparing a phosphazene-based organic metal complex flame-retardant epoxy resin according to claim 1, wherein in the first step, bisphenol a diglycidyl ether epoxy resin is heated to 50 to 180 ℃, the mass of the added organic metal complex constructed based on the cyclotriphosphazene nitrogen heterocyclic ligand is 2 to 20 percent of the total mass of the materials, and the stirring time is 0.5 to 2.0 hours.

5. The preparation method of the phosphazene-based organic metal complex flame-retardant epoxy resin, according to claim 1, is characterized in that in the second step, the mixture obtained in the first step is cooled to 30-120 ℃, the mass of the added curing agent is 6% -36% of that of bisphenol A diglycidyl ether epoxy resin, and after uniform stirring, air in the system is removed in a vacuum oven for 2-10 min.

6. The method as claimed in claim 1, wherein the second step of heating and curing is carried out in two stages, the heating and curing are carried out at 50-120 ℃ for 1-3h, and the heating and curing are carried out at 120-180 ℃ for 3-6 h.

7. An organometallic complex flame-retardant epoxy resin constructed based on cyclotriphosphazene azaheterocyclic ligands prepared by the method of any one of claims 1-6.

Technical Field

The invention designs an organic metal complex flame-retardant epoxy resin based on phosphazene and a preparation method thereof, belonging to the technical field of obtaining flame-retardant epoxy resin materials by adding specific flame-retardant components into common epoxy resin.

Background

In modern society, epoxy resin is widely used in the fields of electronic and electrical materials, engineering and composite materials, building materials, coatings, adhesives and the like due to the characteristics of excellent cohesiveness, chemical stability, good mechanical properties and the like. However, the fire hazard of the epoxy resin is easy to occur due to the inflammability of the epoxy resin, and the epoxy resin is difficult to self-extinguish after ignition and release a large amount of dense smoke, thereby seriously harming the public safety of the society. Therefore, flame retardant modification is an effective way to expand the application field of epoxy resin.

In order to obtain epoxy resins with more excellent flame retardant properties and comprehensive application properties, studies have been made to construct novel flame retardant molecules by compounding a cyclic phosphazene group with other flame retardant elements or functional groups. Among them, the catalytic flame retardant system has been increasingly a hot spot in the flame retardant field due to its advantages of low addition, high char formation efficiency, stable char structure at high temperature, etc. At present, a metal catalytic flame retardant system consisting of inorganic metal oxide/metal salt and traditional flame retardant has a certain synergistic expectation on flame retardant polymers. However, the catalytic efficiency is reduced due to the compatibility between the metal oxide and the flame-retardant group, and the flame-retardant effect is further affected. The organic metal coordination compound designed and synthesized based on cyclotriphosphazene with coordination capacity combines metal elements and phosphazene groups in a coordination bond form to form a flame retardant system with metal catalysis phosphorus-nitrogen synergism, so that the flame retardant system has the functions of smoke suppression and catalysis of the metal elements and the flame retardant function of the phosphazene groups, and the epoxy resin has more excellent flame retardant property due to the synergistic effect among multiple flame retardant element molecules or groups. The complex becomes a catalytic flame retardant with great application prospect, but the research on the flame retardant system of the complex is not common at present.

Disclosure of Invention

The invention aims to provide the organic metal complex flame-retardant epoxy resin based on the phosphazene and the preparation method thereof.

The invention independently uses organic metal complex constructed by cyclophosphazene heterocyclic ligands as a flame retardant to melt and blend with bisphenol A diglycidyl ether epoxy resin at a certain temperature, and adds a curing agent to carry out curing reaction to obtain the epoxy resin cured product with excellent flame retardant property.

The preparation method of the flame-retardant epoxy resin material based on the organic metal complex comprises the following steps:

(1) heating bisphenol A diglycidyl ether epoxy resin, adding an organic metal complex constructed based on a cyclotriphosphazene nitrogen heterocyclic ligand into the epoxy resin, and continuously stirring;

(2) and (3) cooling the treated epoxy resin, adding a curing agent with equivalent weight to epoxy groups in the epoxy resin under the stirring condition, stirring until the curing agent is fully dissolved or dispersed, removing air in a mixed system under the vacuum condition, heating and curing to prepare the flame-retardant epoxy resin material of the organic metal complex constructed by the cyclotriphosphazene nitrogen heterocyclic ligands.

In the invention, the organic metal complex (M-H) is constructed based on cyclotriphosphazene azaheterocyclic ligand₆L^X) The chemical structural formula of (A) is:

the wavy line indicates that the compound is classified into the above structure having a plurality of repetitions.

The synthesis method can adopt the following steps:

(1) firstly, dissolving p-hydroxybenzaldehyde and an acid-binding agent in an organic solvent together, stirring at normal temperature for reaction, adding hexachlorocyclotriphosphazene, heating at 50-80 ℃, stirring for reaction for 8-24h, cooling to room temperature, performing suction filtration, washing with the solvent for multiple times, and drying at 120 ℃ to obtain a intermediate hexa-p-formyl phenoxy cyclotriphosphazene (HAPCP).

(2) Fully dissolving HAPCP in an organic solvent, heating and stirring at 40-70 ℃, adding a nitrogen-containing heterocyclic compound into a reactor after complete dissolution, fully stirring, raising the temperature to 50-80 ℃, distilling at normal pressure, and drying at 120 ℃ for about 2-5 hours to obtain an organic ligand H₆L^X。

(3) Adding the organic ligand H prepared in the step (2) into an organic solvent₆L^XFully stirring and dissolving; adding metal salt into the organic solvent, and fully stirring and dissolving. Mixing the two solutions, heating to reflux state (130-180 deg.C), heating while stirring for 8-24 hr, cooling to room temperature, and vacuum filtering to obtain organic metal coordination compound M-H₆L^X。

The reaction process is as follows:

in the above technical solution, preferably, the raw materials used: bisphenol a diglycidyl ether epoxy resin (DGEBA) (epoxy equivalent values ranging from 0.10 to 0.54, technical grade); M-H₆L^X(purity > 97%, laboratory preparation); the curing agent is one or more of 4,4 '-diaminodiphenyl sulfone (DDS) (purity is more than 98%, industrial grade), 4' -diaminodiphenyl methane (DDM) (purity is more than 98%, industrial grade), m-phenylenediamine (mPDA) (purity is more than 98%, industrial grade), linear phenolic resin (PN) (purity is more than 97%, industrial grade) and m-xylylenediamine (mXDA) (industrial grade).

Preferably, the preparation method of the phosphazene-based organometallic complex flame-retardant epoxy resin comprises the following specific steps:

(1) heating bisphenol A diglycidyl ether epoxy resin with the epoxy value range of 0.10-0.54 to 50-180 ℃, adding an organic metal complex flame retardant accounting for 2-20 percent of the total mass of the materials into the epoxy resin under the condition of stirring, and stirring for 0.5-2.0 hours until the two are uniformly mixed.

(2) Cooling the mixture obtained in the first step to 30-120 ℃, adding a curing agent which is one of 4,4 '-diaminodiphenyl sulfone, 4' -diaminodiphenyl methane, dicyanodiamide, m-phenylenediamine, linear phenolic resin and m-xylylenediamine, wherein the mass of the added curing agent is 6-36% of that of bisphenol A diglycidyl ether epoxy resin, uniformly stirring, removing air in a system in a vacuum oven for 2-10min, then thermally curing for 1-3h at 50-120 ℃, and then heating to 120-180 ℃ for 3-6 h.

The molar ratio of hexachlorocyclotriphosphazene to p-hydroxybenzaldehyde in the step (1) is 1: 6-1: 8; the molar ratio of the acid-binding agent to the p-hydroxybenzaldehyde is 0.5-1.5: 1; the acid-binding agent is one of potassium carbonate, sodium bicarbonate, sodium hydroxide and triethylamine; the organic solvent is one or a combination of more of acetone, tetrahydrofuran, N-dimethylformamide, dimethyl sulfoxide, water and chloroform.

The molar ratio of the HAP to the nitrogen-containing heterocyclic compound in the step (2) is 1: 5-1: 8; the organic solvent is one or a combination of more of acetone, tetrahydrofuran, N-dimethylformamide, dimethyl sulfoxide, water and chloroform.

The metal salt in the step (3) is one or more of calcium acetate, cobalt acetate, zinc acetate, nickel acetate, manganese acetate, iron acetate, copper acetate, palladium acetate, barium acetate, zinc chloride and zinc nitrate; the organic ligand H₆L^XThe molar ratio of the metal salt to the metal salt is 1:3 to 1: 7. By adopting the proportion, the metal coordination is reasonable, the product can have the best flame retardant property, and the heat stability and the carbon residue quantity can be improved.

The flame-retardant epoxy resin material of the organic metal complex constructed based on the cyclotriphosphazene azacylo ligand combines the metal smoke suppression catalysis effect and the phosphorus-nitrogen synergistic flame-retardant effect, can effectively reduce the heat release peak value of the material during combustion, and can obtain better flame-retardant effect under the condition of lower addition amount. Meanwhile, the organic metal complex flame retardant has good compatibility with epoxy resin, and obtains higher thermal stability while ensuring the mechanical property of the matrix materialAnd the flame retardant has carbon forming capability, does not generate dripping and dense smoke during combustion, is an environment-friendly flame retardant with high efficiency, low smoke and high thermal stability, and is used as M-H₆L^XWhen the mass fraction in the system is 9 percent, the limit oxygen index of the bisphenol A glycidyl ether type epoxy resin can reach 32 percent, and the flame retardant grade can reach UL94V-0 grade.

Detailed Description