阅读说明：本技术 包含吡唑阻燃剂的高分子阻燃材料及其制备方法 (High-molecular flame-retardant material containing pyrazole flame retardant and preparation method thereof ) 是由 杨梅 陈瑞 孙传伯 王寅嵩 张珍林 于 2020-03-06 设计创作，主要内容包括：本发明公开了包含吡唑阻燃剂的高分子阻燃材料及其制备方法,该高分子阻燃材料包含如下重量份计的原料：环氧树脂预聚体、吡唑阻燃剂、固化剂,其制备的方法步骤如下：将环氧树脂预聚体升温至60-150℃,然后加入富含吡唑阻燃剂,在真空下搅拌至混合物呈均一透明的状态,接着加入固化剂,完全溶解后,进行固化,得阻燃高分子材料。本发明制备的富含吡唑阻燃剂具有热稳定性好、低烟低毒、力学性能好等特点,同时还具有良好的阻燃性,用于改性环氧树脂,不仅提高环氧树脂的阻燃性能,还能提高其热稳定性和透明度等,使复合材料具有多功能化的特点。(The invention discloses a macromolecular flame-retardant material containing a pyrazole flame retardant and a preparation method thereof, wherein the macromolecular flame-retardant material comprises the following raw materials in parts by weight: the preparation method comprises the following steps: heating the epoxy resin prepolymer to 60-150 ℃, adding a pyrazole-rich flame retardant, stirring in vacuum until the mixture is in a uniform and transparent state, adding a curing agent, completely dissolving, and curing to obtain the flame-retardant high polymer material. The pyrazole-rich flame retardant prepared by the invention has the characteristics of good thermal stability, low smoke, low toxicity, good mechanical property and the like, and also has good flame retardance, and the pyrazole-rich flame retardant is used for modifying epoxy resin, so that the flame retardance of the epoxy resin is improved, the thermal stability, the transparency and the like of the epoxy resin are also improved, and the composite material has the characteristic of multiple functions.)

1. The high-molecular flame-retardant material containing the pyrazole flame retardant is characterized by comprising the following raw materials in parts by weight: 20-30 parts of epoxy resin prepolymer, 1.5-1.8 parts of pyrazole flame retardant and 5-8 parts of curing agent.

2. The polymeric flame retardant material comprising a pyrazole flame retardant of claim 1, wherein the curing agent is 4, 4' -diaminodiphenylmethane.

3. The polymeric flame retardant material comprising a pyrazole flame retardant according to claim 1, wherein the pyrazole flame retardant has a molecular structure as follows:

4. the polymeric flame retardant material comprising a pyrazole flame retardant according to claim 3, wherein the pyrazole flame retardant is synthesized by the following route:

5. the high molecular flame retardant material containing pyrazole flame retardant according to claim 3, wherein the preparation method of the pyrazole flame retardant comprises the following steps:

s1: sequentially adding 5-amino-3-methyl-1-phenylpyrazole, p-benzaldehyde and a first solvent into a reaction vessel, and stirring at 30-180 ℃ for 4-24 h;

s2: adding DOPO into a reaction vessel of S1, and reacting for 4-24h at 30-180 ℃;

s3: and filtering the solution after the reaction in the S2, dissolving the crude product obtained by filtering in a second solvent to remove impurities in the crude product, and drying the solid product after filtering to obtain the pyrazole-rich flame retardant.

6. The polymeric flame retardant material comprising a pyrazole flame retardant according to claim 5, wherein the molar volume ratio of the 5-amino-3-methyl-1-phenylpyrazole, the p-benzaldehyde and the DOPO to the first solvent is 1mol:0.1-10mol:0.1-10mol:5-200 ml.

7. The polymeric flame retardant material comprising pyrazole flame retardants of claim 5, wherein the first solvent is one or more of N, N-dimethylformamide, ethanol, toluene, carbon tetrachloride; the second solvent is dichloromethane or water or a mixed solution thereof.

8. The method of preparing a pyrazole-rich flame retardant of claim 5, wherein the drying conditions in S3 are: vacuum drying at 50-65 deg.C for 20-26 h.

9. The method for preparing the high molecular flame retardant material containing the pyrazole flame retardant according to claim 1, wherein the method comprises the following steps:

heating the epoxy resin prepolymer to 60-150 ℃, adding a pyrazole-rich flame retardant, stirring in vacuum until the mixture is in a uniform and transparent state, adding a curing agent, completely dissolving, and curing to obtain the flame-retardant high polymer material.

10. The method for preparing a polymeric flame retardant material containing a pyrazole flame retardant according to claim 10, wherein the curing conditions are as follows: curing at 90-110 ℃ for 1-5h, at 110-140 ℃ for 1-5h, and at 140-180 ℃ for 1-3 h.

Technical Field

The invention relates to the technical field of organic flame retardants, in particular to a high-molecular flame-retardant material containing a pyrazole flame retardant and a preparation method thereof.

Background

Epoxy resin has the characteristics of excellent mechanical property, corrosion resistance, good compactness and stable chemical property, and is widely applied to various aspects of life such as coating, composite materials, casting materials, adhesives, mould pressing materials, injection molding materials and the like. However, because epoxy resin is flammable, once a fire occurs, most of the fire can spread, and great threat is caused to the economy and life of the people. Therefore, it is an important task to modify the flame retardancy of epoxy resins.

Phosphorus flame retardants are currently considered to be a class of flame retardants with high efficiency and environmental protection, but most of the existing phosphorus flame retardants contain fluorine, and harmful gases with great harm are generated during combustion.

Disclosure of Invention

Based on the technical problems in the background art, the invention provides a macromolecular flame retardant material containing a pyrazole flame retardant and a preparation method thereof, and the flame retardant property of epoxy resin is improved.

The invention provides a high-molecular flame-retardant material containing a pyrazole flame retardant, which comprises the following raw materials in parts by weight: 20-30 parts of epoxy resin prepolymer, 1.5-1.8 parts of pyrazole flame retardant and 5-8 parts of curing agent.

Preferably, the curing agent is 4, 4' -diaminodiphenylmethane.

Preferably, the molecular structure of the pyrazole flame retardant is as follows:

preferably, the synthetic route of the pyrazole flame retardant is as follows:

preferably, the preparation method of the pyrazole flame retardant comprises the following steps:

s1: sequentially adding 5-amino-3-methyl-1-phenylpyrazole, p-benzaldehyde and a first solvent into a reaction vessel, and stirring at 30-180 ℃ for 4-24 h;

s2: adding DOPO into a reaction vessel of S1, and reacting for 4-24h at 30-180 ℃;

s3: and filtering the solution after the reaction in the S2, dissolving the crude product obtained by filtering in a second solvent to remove impurities in the crude product, and drying the solid product after filtering to obtain the pyrazole-rich flame retardant.

Preferably, the molar volume ratio of the 5-amino-3-methyl-1-phenylpyrazole, the p-benzaldehyde and the DOPO and the first solvent is 1mol:0.1-10mol:0.1-10mol:5-200 ml.

Preferably, the first solvent is one or more of N, N-dimethylformamide, ethanol, toluene and carbon tetrachloride; the second solvent is dichloromethane or water or a mixed solution thereof.

Preferably, the drying conditions in S3 are: vacuum drying at 50-65 deg.C for 20-26 h.

The preparation method of the flame-retardant high polymer material rich in the pyrazole flame retardant comprises the following steps:

heating the epoxy resin prepolymer to 60-150 ℃, adding a pyrazole-rich flame retardant, stirring in vacuum until the mixture is in a uniform and transparent state, adding a curing agent, completely dissolving, and curing to obtain the flame-retardant high polymer material.

Preferably, the curing conditions are: curing at 90-110 ℃ for 1-5h, at 110-140 ℃ for 1-5h, and at 140-180 ℃ for 1-3 h.

The action mechanism is as follows:

the phosphorus-containing flame retardant is pyrolyzed at a high temperature to generate P and PO radicals, and H and O radicals generated in the gas phase combustion process are captured by the radicals to reduce the concentration of the radicals, thereby inhibiting the combustion. In addition, the epoxy resin thermosetting material can be promoted to form a carbon layer, which can be used as a physical barrier to prevent flame from spreading to the interior of the material. The flame retardant containing nitrogen elements can release ammonia gas, water vapor, nitric oxide, nitrogen dioxide and other non-combustible gases after being heated and decomposed. The presence of these non-flammable gases greatly reduces the concentration of flammable gases produced by the decomposition of the epoxy resin, thereby reducing the temperature at the surface of the epoxy thermoset.

Compared with the prior art, the invention has the beneficial technical effects that:

(1) the resin matrix contains two flame-retardant elements of phosphorus and nitrogen, and the two flame-retardant elements can not only exert respective flame-retardant advantages in practical application, but also have a synergistic flame-retardant effect, so that the obtained flame-retardant epoxy resin has the characteristics of excellent thermal stability and flame-retardant property, only 5% of flame retardant is required to be added, and the limit oxygen index of the prepared epoxy resin can reach about 30%; in the existing flame retardant DOPO-PHM synthesized by using DOPO, aniline and 4-hydroxybenzaldehyde as raw materials, when the addition amount of the flame retardant exceeds 10%, the limiting oxygen index can reach 29.0%.

(2) The pyrazole-rich flame retardant designed by the invention has the advantages that two ends of the molecular structure contain DOPO, the compatibility in the epoxy resin is good, and the flame retardant can be fully combined with the epoxy resin to obtain the transparent flame-retardant epoxy resin with good comprehensive performance.

Drawings

FIG. 1 is a nuclear magnetic resonance image of a pyrazole-rich flame retardant according to the present invention;

FIG. 2 is an infrared spectrum of a pyrazole-rich flame retardant according to the present invention;

FIG. 3 is an electron micrograph of an epoxy resin comprising a pyrazole-rich flame retardant of the present invention after combustion.

Detailed Description

The present invention will be further illustrated with reference to the following specific examples.