阅读说明：本技术 一种高效膦-氮阻燃剂及其制备方法和应用 (Efficient phosphine-nitrogen flame retardant and preparation method and application thereof ) 是由 许苗军 刘鲁斌 李斌 于 2020-05-21 设计创作，主要内容包括：一种高效膦-氮阻燃剂及其制备方法和应用,涉及一种阻燃剂及其制备方法和应用。是要解决现有含磷阻燃剂存在阻燃效率低、热稳定性不高的问题。膦-氮型阻燃剂的制备方法：一、向反应器中加入无水哌嗪、氯仿、三乙胺,搅拌；将苯基磷酰二氯溶于氯仿,滴加到反应器中反应,萃取,浓缩,得到粗产品,干燥得中间体；二、将中间体和氯仿加入到反应器中,加三乙胺；将二苯基次磷酰氯溶于氯仿中,滴加到反应器,回流反应；洗涤,浓缩,干燥,得到膦-氮阻燃剂。该膦-氮型阻燃剂用于阻燃改性聚乳酸中的应用。本发明合成的膦-氮阻燃剂具有良好的热稳定性、耐水解性能,是集气相和凝聚相阻燃为一体的高效膦-氮阻燃剂。本发明应用于阻燃剂领域。(A high-efficiency phosphine-nitrogen flame retardant and a preparation method and application thereof relate to a flame retardant and a preparation method and application thereof. The flame retardant aims to solve the problems of low flame retardant efficiency and low thermal stability of the existing phosphorus-containing flame retardant. The preparation method of the phosphine-nitrogen flame retardant comprises the following steps: firstly, adding anhydrous piperazine, chloroform and triethylamine into a reactor, and stirring; dissolving phenyl phosphoryl dichloride in chloroform, dropwise adding the mixture into a reactor for reaction, extracting and concentrating to obtain a crude product, and drying to obtain an intermediate; secondly, adding the intermediate and chloroform into a reactor, and adding triethylamine; dissolving diphenyl phosphoryl chloride in chloroform, dropwise adding the solution into a reactor, and carrying out reflux reaction; washing, concentrating and drying to obtain the phosphine-nitrogen flame retardant. The phosphine-nitrogen flame retardant is applied to flame-retardant modified polylactic acid. The phosphine-nitrogen flame retardant synthesized by the invention has good thermal stability and hydrolysis resistance, and is a high-efficiency phosphine-nitrogen flame retardant integrating gas phase flame retardance and condensed phase flame retardance. The invention is applied to the field of flame retardants.)

1. A high-efficiency phosphine-nitrogen flame retardant is characterized in that the flame retardant is [4,4' - (phenylphosphoryl) bis (4, 1-dipiperazinyl) ] bis (diphenylphosphine oxide), and the structural formula is as follows:

2. the method for preparing a phosphine-nitrogen type flame retardant according to claim 1, comprising the steps of:

firstly, adding anhydrous piperazine and chloroform into an anhydrous and oxygen-free reactor, stirring at the temperature of-6 to-4 ℃ until the piperazine is completely dissolved in the chloroform, then adding triethylamine into the reactor, and fully stirring;

dissolving phenyl phosphoryl dichloride in chloroform to obtain a mixed solution A, then dropwise adding the mixed solution A into a reactor, keeping the temperature of the solution in the reactor at-6 to-4 ℃, continuously keeping the temperature at-6 to-4 ℃ for 30-40 min after dropwise adding, then raising the reaction temperature to 25-26 ℃, continuously reacting for 2-3 h, directly pouring reactants into water after the reaction is finished, then extracting a lower chloroform layer, and concentrating to obtain a crude product; drying the crude product to obtain a light yellow solid, namely an intermediate phenyl bis (1-piperazinyl) phosphine oxide;

secondly, adding the intermediate synthesized in the step one and chloroform into a reactor, stirring until the intermediate and the chloroform are dissolved, then adding an acid-binding agent triethylamine, and reducing the reaction temperature to-6 to-4 ℃;

dissolving diphenylphosphinic chloride in chloroform to obtain a mixed solution B, then dropwise adding the mixed solution B into a reactor, keeping the temperature of the solution in the reactor between-6 ℃ and-4 ℃, continuously keeping the temperature between-6 ℃ and-4 ℃ for 30-40 min after dropwise adding, then raising the reaction temperature to 62-65 ℃, and keeping reflux reaction for 12-14 h;

after the reaction is finished, pouring the reactant into water for washing, then separating the lower chloroform layer, concentrating to obtain a light yellow product, and drying to obtain a final product [4,4' - (phenylphosphoryl) bis (1, 4-dipiperazino) ] bis (diphenylphosphine oxide), namely the phosphine-nitrogen flame retardant.

3. The method for preparing a phosphine-nitrogen type flame retardant according to claim 2, wherein the mass ratio of the anhydrous piperazine to the chloroform in the step one is 1 (8-10), and the molar ratio of the anhydrous piperazine to the triethylamine is 1 (2-2.2).

4. The method for preparing a phosphine-nitrogen type flame retardant according to claim 2, wherein the mass ratio of the phenylphosphoryl dichloride to the chloroform in the step one is 1 (1-1.5).

5. Use of the phosphine-nitrogen based flame retardant of claim 1 in flame retardant modified polylactic acid.

6. The use according to claim 5, characterized in that the specific method of the flame retardant modified polylactic acid is as follows:

mixing a phosphine-nitrogen flame retardant [4,4' - (phenyl phosphoryl) bis (1, 4-dipiperazino) ] bis (diphenylphosphine oxide) and polylactic acid, heating, melting and blending for 15-20 min, taking out the mixed material, and performing hot press molding to obtain the modified polylactic acid.

7. Use according to claim 6, characterized in that the mass of the phosphine-nitrogen flame retardant is between 1% and 6% of the mass of the polylactic acid.

8. Use according to claim 6, characterized in that the mass of the phosphine-nitrogen flame retardant is between 3% and 4% of the mass of the polylactic acid.

9. The use according to claim 6 or 7, characterized in that the heating melt blending is carried out by a torque rheometer, the temperature of each heating zone being 180 ℃, 180 ℃ and 180 ℃, respectively, and the rotation speed being 50 r/min.

10. The use according to claim 6 or 7, characterized in that the specific method of hot press forming is: and putting the mixed material on a flat vulcanizing machine, and carrying out hot press molding at 180 ℃ under the pressure of 10 MPa.

Technical Field

The invention relates to a flame retardant, a preparation method and application thereof.

Background

The polylactic acid (PLA) has the advantages of wide raw material source, easy processing and forming, excellent mechanical property, excellent biocompatibility and degradability, and the like, and is widely applied to the fields of biological medicine, spinning, packaging, and the like. However, the PLA material is flammable, has high combustion speed and is not easy to extinguish, and meanwhile, a large amount of molten drops are generated, so that the use of the PLA in some fields is limited. Therefore, flame retardant modification of PLA is needed.

The halogen-containing flame retardant releases more smoke and toxic gases in the combustion process, and the application of the halogen-containing flame retardant is limited to a certain extent. The inorganic flame retardant is low in price, low in smoke and low in toxicity, but the inorganic flame retardant is often added in a large amount, influences the mechanical and processing performances of the PLA material and has insufficient toughness. In recent years, organic phosphorus flame retardants have been widely used for flame retardant modification of high polymers due to their advantages of low smoke and low toxicity. With the development of science and technology, products in the fields of electronics and the like are developed towards miniaturization and ultra-thinning, and higher requirements are put forward on flame-retardant polymer materials. The material not only needs to have excellent flame retardant property, but also has excellent weather resistance, processing, mechanical property and the like. Therefore, the flame retardant to be prepared has high flame retardant efficiency for PLA materials, and simultaneously has good thermal stability, hydrolysis resistance and other properties. The phosphorus-containing flame retardant used for PLA at present is a compound containing O ═ P-O bonds, and has the problems of low flame retardant efficiency, unsatisfactory thermal stability, easiness in hydrolysis, difficulty in processing and dispersion and the like.

Disclosure of Invention

The invention aims to solve the problems of low flame retardant efficiency and low thermal stability of the existing phosphorus-containing flame retardant, and provides a high-efficiency phosphine-nitrogen flame retardant, and a preparation method and application thereof.

The phosphine-nitrogen flame retardant is [4,4' - (phenyl phosphoryl) bis (4, 1-dipiperazinyl) ] bis (diphenyl phosphine oxide), and the structural formula is as follows:

the preparation method of the phosphine-nitrogen type flame retardant comprises the following steps:

firstly, adding anhydrous piperazine and chloroform into an anhydrous and oxygen-free reactor, stirring at the temperature of-6 to-4 ℃ until the piperazine is completely dissolved in the chloroform, then adding triethylamine into the reactor, and fully stirring;

dissolving phenyl phosphoryl dichloride in chloroform to obtain a mixed solution A, then dropwise adding the mixed solution A into a reactor, keeping the temperature of the solution in the reactor at-6 to-4 ℃, continuously keeping the temperature at-6 to-4 ℃ for 30-40 min after dropwise adding, then raising the reaction temperature to 25-26 ℃, continuously reacting for 2-3 h, directly pouring reactants into water after the reaction is finished, washing away triethylamine hydrochloride, then extracting a lower chloroform layer, and concentrating to obtain a crude product; drying the crude product to obtain a light yellow solid, namely an intermediate phenyl bis (1-piperazinyl) phosphine oxide;

secondly, adding the intermediate synthesized in the step one and chloroform into a reactor, stirring until the intermediate and the chloroform are dissolved, then adding an acid-binding agent triethylamine, and reducing the reaction temperature to-6 to-4 ℃;

dissolving diphenylphosphinic chloride in chloroform to obtain a mixed solution B, then dropwise adding the mixed solution B into a reactor, keeping the temperature of the solution in the reactor between-6 ℃ and-4 ℃, continuously keeping the temperature between-6 ℃ and-4 ℃ for 30-40 min after dropwise adding, then raising the reaction temperature to 62-65 ℃, and keeping reflux reaction for 12-14 h;

after the reaction is finished, pouring the reactant into water for washing, removing triethylamine hydrochloride, then separating a lower chloroform layer, concentrating to obtain a light yellow product, and drying to obtain a final product [4,4' - (phenylphosphoryl) bis (1, 4-dipiperazinyl) ] bis (diphenylphosphine oxide), namely the phosphine-nitrogen flame retardant.

Furthermore, in the first step, the mass ratio of the anhydrous piperazine to the chloroform is 1 (8-10), and the molar ratio of the anhydrous piperazine to the triethylamine is 1 (2-2.2).

Furthermore, in the first step, the mass ratio of the phenylphosphoryl dichloride to the chloroform is 1 (1-1.5).

The phosphine-nitrogen flame retardant is applied to flame-retardant modified polylactic acid.

Further, the specific method of the flame-retardant modified polylactic acid comprises the following steps:

mixing a phosphine-nitrogen flame retardant [4,4' - (phenyl phosphoryl) bis (1, 4-dipiperazino) ] bis (diphenylphosphine oxide) and polylactic acid, heating, melting and blending for 15-20 min, taking out the mixed material, and performing hot press molding to obtain the modified polylactic acid.

Wherein the mass of the phosphine-nitrogen flame retardant is 1 to 6 percent of that of the polylactic acid.

Further, the heating, melting and blending are carried out by a torque rheometer, the temperature of each heating zone is 180 ℃, 180 ℃ and 180 ℃, and the rotating speed is 50 r/min.

Further, the hot press molding method comprises the following specific steps: and putting the mixed material on a flat vulcanizing machine, and carrying out hot press molding at 180 ℃ under the pressure of 10 MPa.

The reaction principle of the invention is as follows:

the invention takes phenylphosphoryl dichloride, diphenylphosphine chloride and piperazine as raw materials to prepare the high-efficiency phosphine-nitrogen flame retardant [4,4' - (phenylphosphoryl) bis (4, 1-dipiperazino) ] bis (diphenylphosphine oxide). The synthetic route of the phosphine-nitrogen flame retardant is as follows:

the invention has the beneficial effects that:

the phosphine-nitrogen flame retardant synthesized by the invention contains P-C and P-N bond structures, has good thermal stability and hydrolysis resistance, is a high-efficiency phosphine-nitrogen flame retardant integrating gas phase and condensed phase flame retardance, is light yellow or white powder, and has the synthesis yield of a target product of more than 92 percent. Thermogravimetric analysis tests show that the flame retardant has an initial thermal decomposition temperature of 336.3 ℃, has excellent thermal stability, can meet the processing requirements of most high polymer materials such as PLA and the like, has a char forming amount of 10.4 wt% at 800 ℃, and has good char forming performance.

Meanwhile, the flame retardant has good compatibility with a polymer base material, is not easy to migrate and precipitate in the material, can be washed by water, has good water resistance, and overcomes the problems of poor water resistance, easy precipitation and the like of the traditional micromolecular organic phosphorus flame retardant.

Compared with the prior synthesis technology of some phosphorus-containing flame retardants, the synthesis method disclosed by the invention is relatively simple, no catalyst is needed in the synthesis process, the solvent can be recycled, the high-temperature high-pressure reaction is not involved, the energy consumption is low, the synthesis yield of the target product is higher, and the application prospect is better.

When the phosphine-nitrogen flame retardant is added into a PLA material, and the addition amount is only 4 wt%, the flame-retardant polylactic acid composite material reaches UL-94V-0 grade in a vertical combustion test, and the Limiting Oxygen Index (LOI) is increased to 29.4 percent from 19.0 percent of a pure PLA material. The flame retardant has excellent flame retardant efficiency on PLA materials, and the influence on the mechanical property, the processing property and the like of the materials is small due to the low addition amount of the flame retardant, so that the high-efficiency flame-retardant polylactic acid material with excellent comprehensive properties is prepared.

Drawings

FIG. 1 is a Fourier Transform Infrared (FTIR) spectrum of an intermediate phenylbis (1-piperazinyl) phosphine oxide;

FIG. 2 is an infrared spectrum of the product [4,4' - (phenylphosphoryl) bis (4, 1-dipiperazinyl) ] bis (diphenylphosphine oxide) (PDPO) and the reactant diphenylphosphinic chloride (DPPC);

FIG. 3 is a diagram of PDPO product¹³C NMR spectrum;

FIG. 4 is a diagram of PDPO product³¹A P NMR spectrum;

figure 5 is a DTG and TGA plot of the product PDPO as measured by thermogravimetric analysis.

Detailed Description

The technical solution of the present invention is not limited to the following specific embodiments, but includes any combination of the specific embodiments.