CN102875842A - Phosphorus-nitrogen intumescent flame retardant and preparation method thereof - Google Patents

Abstract

A phosphorus nitrogen intumescent flame retardant and a preparation method thereof, relating to a chemical synthesis agent and a preparation method thereof, the preparation raw materials include: cyanuric chloride, 9,10-dihydro-9-oxa-10-phospha Phenanthrene-10-oxide (DOPO) and formaldehyde solution, the method for preparing the flame retardant is divided into two steps, the first step is to react DOPO and formaldehyde under certain conditions to generate phosphorus-containing intermediate DOPOCH ₂ OH; In the second step, DOPOCH ₂ OH and cyanuric chloride are stirred and reacted for a certain period of time under the introduction of inert gas, and the product is recrystallized and dried, and the obtained white powder is the phosphorus nitrogen intumescent flame retardant. The compound has high thermal stability, expansibility and char formation rate, and can be used as a flame retardant additive in various polymers to improve the flame retardant performance of the polymer. The process of the invention has simple production conditions, high product purity and yield, and convenient post-treatment process.

Description

A kind of phosphorus nitrogen intumescent flame retardant and preparation method thereof

technical field

The invention relates to a chemical synthesis agent and a preparation method thereof, in particular to a phosphorus-nitrogen intumescent flame retardant and a preparation method thereof.

Background technique

Materials are the pillars of the relationship between modern science and social development. Polymer materials have many incomparable properties with other materials, and have become indispensable materials in various fields of cutting-edge technology, national defense construction and national economy. However, most polymer compounds are flammable and combustible materials. In recent decades, a considerable part of the fires in the world are related to the burning of polymer materials.

Therefore, how to improve the flame retardancy of materials has become a topic of great concern all over the world. As synthetic materials play an increasingly important role in national economic construction, it stimulates and promotes the rapid development of flame retardant technology. Flame retardant is one of the important additives for the modification of polymer materials, and its function is to make synthetic materials flame retardant, self-extinguishing and smoke extinguishing.

Halogenated flame retardants are currently the most used and produced organic flame retardants in my country. They are widely used in the flame retardant modification of various polymer materials and occupy a particularly important position in flame retardants. However, relevant studies have shown that halogenated flame retardants will produce a large amount of corrosive and toxic gases during use, recycling and burning, which will pollute the environment and endanger human health. On February 13, 2003, the European Union issued the "Waste Electrical and Electronic Equipment Act" (WEEE) and the "Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment Directive" (RoHS), which clearly prohibits the use of halogen-containing electrical and electronic products in Sold within EU countries. The Ministry of Information Industry of my country has also promulgated the "Administrative Measures for the Control of Pollution by Electronic Information Products" to control the use of toxic and harmful substances in electronic products.

Therefore, the advancement of science and the improvement of environmental protection awareness require people not only to develop flame retardants with better performance, but also to put forward stricter requirements for the flame retardant itself and the environmental protection issues in the use process. Toxicization, compounding, and smoke suppression have become the overall development trend of flame retardants in the 21st century. Flame retardant developers and application companies at home and abroad have been adjusting the product structure of flame retardants, reducing the use of halogenated flame retardants, and increasing the development and research of highly efficient and environmentally friendly halogen-free flame retardants. However, there are still very few varieties of halogen-free flame retardants that can be applied to the market at present, and it is urgent to develop new products suitable for industrialization.

At present, the halogen-free flame retardants that have been studied at home and abroad mainly include phosphorus, nitrogen, boron, silicon, inorganic hydroxides and composite intumescent flame retardants, but these flame retardants have problems such as relative Due to problems such as poor compatibility, easy leakage, poor thermal stability, and high price, there are still very few excellent flame retardants that can be widely used, and they need to be further studied by scientific researchers.

Contents of the invention

The object of the present invention is to provide a phosphorus nitrogen intumescent flame retardant and a preparation method thereof. It contains two kinds of flame retardant elements, phosphorus and nitrogen. It has the characteristics of high flame retardant efficiency, halogen-free, low smoke, and low toxicity. It meets the requirements of people today to protect the ecological environment. This flame retardant greatly reduces toxic gases during combustion. and generation of corrosive gases.

The purpose of the present invention is achieved through the following technical solutions:

A phosphorus nitrogen intumescent flame retardant, the preparation raw materials of the phosphorus nitrogen intumescent flame retardant include: cyanuric chloride, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxid (DOPO), formaldehyde solution, flame retardant has the following structure:

。

.

A preparation method of phosphorus nitrogen intumescent flame retardant, the preparation method of the flame retardant is carried out in two steps, the first step, reacting DOPO and formaldehyde in a solvent to generate phosphorus-containing intermediate DOPOCH ₂ OH; the second step , DOPOCH ₂ OH and cyanuric chloride are stirred and reacted under the introduction of an inert gas, and the product is subjected to suction filtration, washing, recrystallization, and drying, and the obtained white powder is a phosphorus-nitrogen intumescent flame retardant;

The above process is expressed by chemical reaction formula as:

。

.

In the preparation method of a phosphorus-nitrogen intumescent flame retardant, in the first step of synthesizing the phosphorus-containing intermediate DOPOCH ₂ OH, the molar ratio of DOPO and formaldehyde is 1:1 to 1:10; the solvent used is methanol, Any one of ethanol, propanol, butanol, water or a mixture in any proportion.

In the preparation method of the phosphorus-nitrogen intumescent flame retardant, in the first step of synthesizing the phosphorus-containing intermediate DOPOCH ₂ OH, the reaction temperature is controlled at 0-100° C.; the reaction time is 1-10 hours.

In the method for preparing a phosphorus-nitrogen intumescent flame retardant, in the second step, the inert gas used is nitrogen, or argon or helium.

The preparation method of a kind of phosphorus-nitrogen intumescent flame retardant, in the second step, the reaction is carried out under solvent-free conditions or using any solvent condition of acetone, toluene, ethyl acetate, acetonitrile, tetrahydrofuran and water .

In the preparation method of the phosphorus-nitrogen intumescent flame retardant, in the second step, the reaction temperature is 0-200°C.

In the preparation method of the phosphorus-nitrogen intumescent flame retardant, in the second step, the reaction time is 1-24 hours.

In the preparation method of a novel phosphorus-nitrogen intumescent flame retardant, in the second step, the recrystallization solvent is any one of methanol, ethanol, propanol, ethyl acetate and water or a mixture thereof in any proportion.

In the preparation method of the novel phosphorus-nitrogen intumescent flame retardant, in the second step, the drying temperature is 50-200°C.

Advantage and effect of the present invention are:

Halogen-free intumescent flame retardant is a new type of composite flame retardant that has attracted wide attention in the international flame retardant field in recent years. It contains two flame retardant elements, phosphorus and nitrogen, and has the characteristics of high flame retardant efficiency, halogen-free, low smoke, low toxicity, etc. It meets the requirements of people today to protect the ecological environment, and is considered to be one of the development directions of today's halogen-free flame retardant materials. . Intumescent flame retardants form a dense porous carbon foam layer on the surface of the material through the synergistic effect of acid source, carbon source, and gas source when the polymer is burned. The release of gas to the surface, in turn, blocks the transfer of heat to the polymer and the source of oxygen, thereby preventing the spread and propagation of the flame. Compared with traditional halogen flame retardants, this flame retardant greatly reduces the generation of toxic and corrosive gases during combustion.

Detailed ways

The present invention will be described in detail below in conjunction with examples.

Example 1:

Step 1: Add 54.05g of DOPO and 200ml of absolute ethanol to a 500ml three-necked bottle equipped with a reflux condenser, a thermometer, a constant pressure dropping funnel and a magnet. The temperature was raised to 70°C and 63.74 g of formaldehyde solution was added dropwise. After the dropwise addition, the reaction was carried out at 80° C. for 4 hours. After the reaction was completed, most of the solvent was distilled off under reduced pressure, and a large amount of crystals precipitated when the temperature was lowered to room temperature. After suction filtration, the filter cake was washed with a small amount of absolute ethanol, recrystallized with absolute ethanol, and vacuum-dried at 50°C to obtain 41.64 g of a white solid, namely DOPOCH ₂ OH.

Step 2: Add 3.69 grams of cyanuric chloride, 17.23 grams of _DOPOCH OH and 180 ml of acetonitrile into a 250 ml three-necked flask equipped with a reflux condenser, a thermometer, a nitrogen gas inlet tube and a magnet, and control the temperature at 5°C for 2 hours. Raise the temperature to room temperature and react for 2 hours, then raise the temperature to 70°C and react for 10 hours. After the reaction, cool down to room temperature, filter with suction, wash the filter cake with a small amount of absolute ethanol, recrystallize with ethyl acetate, and dry in vacuum at 80°C to obtain a white powder Phosphorus nitrogen intumescent flame retardant 14.5 grams, yield 89.1%.

Example 2:

Step 1: The synthesis method of phosphorus-containing intermediate DOPOCH ₂ OH is the same as that in Example 1.

Step 2: Add 3.69 grams of cyanuric chloride and 17.23 grams of DOPOCH ₂ OH to a 100ml three-necked flask equipped with a reflux condenser, a thermometer, a nitrogen gas introduction tube and an electric stirrer, and raise the temperature to 150°C under the introduction of nitrogen gas to react until there is no acid gas released, the reaction product was dissolved and washed with anhydrous methanol, filtered with suction, the filter cake was washed with a small amount of anhydrous methanol, recrystallized from ethyl acetate, and vacuum-dried at 80°C to obtain 15.2 grams of white powdery phosphorus-nitrogen intumescent flame retardant, yield 93.4%.

Claims (10)

1. a phosphorus nitrogen expansion type combustion inhibitor is characterized in that, described phosphorus nitrogen expansion type combustion inhibitor raw materials comprises: cyanuric chloride, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), formaldehyde solution, and fire retardant has following structure:

。

2. the preparation method of a phosphorus nitrogen expansion type combustion inhibitor is characterized in that, the preparation method of this fire retardant is that two steps are carried out, and the first step is reacted DOPO and formaldehyde to the phosphorous intermediate DOPOCH of generation in solvent ₂OH; Second step is with DOPOCH ₂OH and cyanuric chloride be stirring reaction under rare gas element imports, and product is through suction filtration, washing, recrystallization, drying treatment, and the gained white powder is the phosphorus nitrogen expansion type combustion inhibitor;

Said process is expressed as with chemical equation:

。

3. the preparation method of a kind of phosphorus nitrogen expansion type combustion inhibitor according to claim 2 is characterized in that, at the synthetic phosphorous intermediate DOPOCH of the first step ₂Among the OH, DOPO and formaldehyde molar ratio are that 1:1 is to 1:10; Solvent for use is the mixture of any one or its arbitrary proportion in methyl alcohol, ethanol, propyl alcohol, butanols, the water.

4. the preparation method of a kind of phosphorus nitrogen expansion type combustion inhibitor according to claim 2 is characterized in that, at the synthetic phosphorous intermediate DOPOCH of the first step ₂Among the OH, temperature of reaction is controlled at 0-100 ℃; Reaction times is 1-10 hour.

5. the preparation method of a kind of phosphorus nitrogen expansion type combustion inhibitor according to claim 2 is characterized in that, in second step, used rare gas element is nitrogen or argon gas or helium.

6. the preparation method of a kind of phosphorus nitrogen expansion type combustion inhibitor according to claim 2, it is characterized in that, in second step, carry out under reaction any one solvent condition in condition of no solvent or employing acetone, toluene, ethyl acetate, acetonitrile, tetrahydrofuran (THF) and water.

7. the preparation method of a kind of phosphorus nitrogen expansion type combustion inhibitor according to claim 2 is characterized in that, in second step, temperature of reaction is 0-200 ℃.

8. the preparation method of a kind of phosphorus nitrogen expansion type combustion inhibitor according to claim 2 is characterized in that, in second step, the reaction times is 1-24 hour.

9. the preparation method of a kind of novel phosphor nitrogen expansion type flame retardant according to claim 1 is characterized in that, in second step, recrystallization solvent is the mixture of any one or its arbitrary proportion in methyl alcohol, ethanol, propyl alcohol, ethyl acetate and the water.

10. the preparation method of a kind of novel phosphor nitrogen expansion type flame retardant according to claim 2 is characterized in that, in second step, drying temperature is 50-200 ℃.