1. The preparation method of the dendritic nitrogen-phosphorus compound is characterized by comprising the following steps of:

and (2) placing the amino-terminated polyamide-amine dendritic compound and the phosphorus-containing compound into a three-neck flask, continuously stirring, adding an acid-binding agent and a solvent, and reacting at 20-60 ℃ for 3-30 hours to obtain the dendritic nitrogen-phosphorus compound.

2. The method of claim 1, wherein the molar ratio of the amino-terminated polyamidoamine dendrimer to the phosphorus-containing compound is from 1:4 to 1: 128.

3. The method of claim 1, wherein the amino-terminated polyamidoamine dendrimer is selected from at least one of the G0-G5 generations of dendrimers with different cores.

4. The method according to claim 1, wherein the phosphorus-containing compound is at least one selected from phosphoric acid, tributyl phosphate, hydroxyethylidene diphosphonic acid, chlorophosphate, diphenyl phosphate, ethylenediamine tetramethylene phosphonic acid, triethyl phosphate, polyaminopolyether methylene phosphonic acid, 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, aminotrimethylene phosphonic acid, diethylenetriamine pentamethylene phosphonic acid, bis 1, 6-hexylene triamine pentamethylene phosphonic acid.

5. The preparation method according to claim 1, wherein the acid scavenger is at least one selected from diethylamine, triethylamine, pyridine, sodium bicarbonate, sodium carbonate, and sodium hydroxide; the solvent is at least one selected from chloroform, N-dimethylformamide, N-dimethylacetamide, diethyl ether, methanol, ethanol, isopropanol, tetrahydrofuran, acetonitrile, dimethyl sulfoxide and dichloromethane.

6. A dendritic nitrogen phosphorus compound, prepared by the method of any one of claims 1 to 5.

7. The dendritic nitrogen-phosphorus compound according to claim 6, wherein the mass fraction of phosphorus in the dendritic nitrogen-phosphorus compound is 8.5 to 14.6% and the mass fraction of nitrogen is 39.8 to 47%.

8. The dendritic nitrogen-phosphorus compound according to claim 7, wherein the mass ratio of N/P in the dendritic nitrogen-phosphorus compound is 2.7-5.5: 1.

9. Use of a dendritic nitrogen phosphorus compound according to any one of claims 6 to 8 in flame retardants.

10. A flame retardant comprising the dendritic nitrogen phosphorus compound according to any one of claims 6 to 8.

Background

In recent years, with the development of flame retardant materials and the rapid expansion of market demands, flame retardants having high efficiency, environmental friendliness, and versatility have attracted more and more attention. With the increasing requirements of human beings on environmental protection and health and the emergence of regulations for limiting and prohibiting the use of halogen flame retardants, halogen flame retardants widely used in the market face a great challenge. The restriction of national and international laws and regulations on halogen flame retardants makes the demand for halogen-free flame retardants increasingly strong. The nitrogen-phosphorus flame retardant is used as a halogen-free intumescent flame retardant, is widely applied to flame retardant modified polymers along with the rise of flame retardant technology, and the polymer containing nitrogen and phosphorus elements has good thermal stability and flame retardance and has the following advantages as a flame retardant: after the chlorine atoms are substituted by the halogen-free groups, the halogen-free halogen free flame retardant rubber composition is free flame retardant flame; the flame retardant is rich in N, P two elements, and has high synergistic flame retardant efficiency; strong reactivity, easy functional modification and various types. Therefore, the nitrogen-phosphorus polymer has good market prospect as a flame retardant and is a perfect substitute product of a halogen flame retardant. When the nitrogen and phosphorus polymer is heated, a uniform carbon foam layer can be generated on the surface of the nitrogen and phosphorus polymer, so that the nitrogen and phosphorus polymer has the functions of heat insulation, oxygen isolation and smoke suppression, and prevents the generation of molten drop, thereby having good flame retardant property.

Chinese patent CN102964632A discloses a dendritic phosphorus-nitrogen flame retardant, a preparation method and application thereof, wherein the dendritic phosphorus-nitrogen flame retardant is prepared by reacting a first generation polyamide-amine, a second generation polyamide-amine and diphenyl chlorophosphate. Specifically, the zero generation, first generation and second generation polyamide-amine reacts with diphenyl chlorophosphate, and the dendritic phosphorus-nitrogen flame retardant is obtained by separation at 0-80 ℃ for 2-10 hours in the presence of a solvent and an acid-binding agent.

However, the dendritic phosphorus-nitrogen flame retardant structure obtained by the technical scheme is obtained by grafting a group containing P on the basis of a polymer containing N, the preparation process is complex, and the flame retardant effect of the obtained flame retardant is limited.

Disclosure of Invention

Aiming at the defects in the prior art, the technical problem to be solved by the invention is to overcome the technical problems of complex preparation process and limited flame retardant effect of the existing dendritic phosphorus-nitrogen flame retardant, and provide a dendritic nitrogen-phosphorus flame retardant which has the characteristics of simple preparation method, perfect retention of dendritic structure, accurate control of P, N content and good flame retardant effect, a preparation method and application thereof, and a flame retardant.

In order to solve the technical problem, the technical scheme adopted by the invention is as follows:

the invention provides a preparation method of a dendritic nitrogen-phosphorus compound, which comprises the following steps:

and (2) placing the amino-terminated polyamide-amine dendritic compound and the phosphorus-containing compound into a three-neck flask, continuously stirring, adding an acid-binding agent and a solvent, and reacting at 20-60 ℃ for 3-30 hours to obtain the dendritic nitrogen-phosphorus compound.

Preferably, the molar ratio of the amino-terminated polyamidoamine dendrimer to the phosphorus-containing compound is from 1:4 to 1: 128.

Preferably, the amino-terminated polyamidoamine dendrimers are selected from at least one of the G0-G5 dendrimeric polyamidoamines.

Preferably, the phosphorus-containing compound is selected from at least one of phosphoric acid, tributyl phosphate, hydroxyethylidene diphosphonic acid, chlorophosphate, diphenyl phosphate, ethylenediamine tetramethylene phosphonic acid, triethyl phosphate, polyaminopolyether methylene phosphonic acid, 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, aminotrimethylene phosphonic acid, diethylenetriamine pentamethylene phosphonic acid, bis 1, 6-hexylidene triamine pentamethylene phosphonic acid.

Preferably, the acid-binding agent is at least one selected from diethylamine, triethylamine, pyridine, sodium bicarbonate, sodium carbonate and sodium hydroxide; the solvent is at least one selected from chloroform, N-dimethylformamide, N-dimethylacetamide, diethyl ether, methanol, ethanol, isopropanol, tetrahydrofuran, acetonitrile, dimethyl sulfoxide and dichloromethane.

The invention also provides a dendritic nitrogen-phosphorus compound prepared by any one of the preparation methods.

Preferably, the mass fraction of phosphorus in the dendritic nitrogen-phosphorus compound is 8.5% -14.6%, and the mass fraction of nitrogen is 39.8% -47%.

Preferably, the mass ratio of N/P in the dendritic nitrogen-phosphorus compound is 2.7-5.5: 1.

The invention also provides application of the dendritic nitrogen-phosphorus compound in a flame retardant.

The invention also provides a flame retardant which comprises the dendritic nitrogen-phosphorus compound.

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

1. the invention provides a preparation method of dendritic nitrogen and phosphorus compounds, which adopts amino-terminated polyamide-amine dendritic compounds and phosphorus-containing compounds as raw materials, has short reaction period, simple production process and low cost, and can meet the requirement of industrial large-scale production, and the preparation method perfectly maintains the dendritic structure and accurately controls the content of P, N;

2. the dendritic nitrogen-phosphorus compound prepared by the method has high nitrogen content;

3. when the dendritic nitrogen-phosphorus compound is used as a flame retardant, a large amount of nitrogen is generated during combustion due to high nitrogen content, so that oxygen is isolated, and the dendritic nitrogen-phosphorus compound has a good flame retardant effect.

Detailed Description

The technical solutions in the embodiments of the present invention will be fully described in detail below. It is obvious that the described embodiments are only some specific embodiments, not all embodiments, of the general technical solution of the present invention. All other embodiments, which can be derived by a person skilled in the art from the general idea of the invention, fall within the scope of protection of the invention.

The invention provides a preparation method of a dendritic nitrogen-phosphorus compound, which comprises the following steps:

and (2) placing the amino-terminated polyamide-amine dendritic compound and the phosphorus-containing compound into a three-neck flask, continuously stirring, adding an acid-binding agent and a solvent, and reacting at 20-60 ℃ for 3-30 hours to obtain the dendritic nitrogen-phosphorus compound. The method adopts the amino-terminated polyamide-amine dendritic compound and the phosphorus-containing compound as raw materials, has short reaction period, simple production process and low cost, and can meet the requirement of industrial large-scale production. It is understood that the reaction temperature may be any value within the range of 25 deg.C, 30 deg.C, 35 deg.C, 40 deg.C, 45 deg.C, 50 deg.C, 55 deg.C, and the reaction time may be 5 hours, 10 hours, 15 hours, 20 hours, 25 hours. Further, the method comprises the steps of washing the dendritic nitrogen-phosphorus compound to be neutral by deionized water, and carrying out reduced pressure distillation and drying to obtain the purified dendritic nitrogen-phosphorus compound. The invention provides a dendritic nitrogen-phosphorus compound, which perfectly maintains a dendritic structure and accurately controls the content of P, N. In addition, in order to ensure the stirring effect, a stirrer can be arranged in the three-neck flask so as to control the stirring at any time according to the requirement.

In a preferred embodiment, the molar ratio of the amino-terminated polyamidoamine dendrimer to the phosphorus-containing compound is from 1:4 to 1: 128. This example specifically defines the molar ratio of the amino-terminated polyamidoamine dendrimer to the phosphorus-containing compound within this range effective to promote reaction of the two to form the high nitrogen-phosphorus content dendrimer protected in accordance with the present invention, which facilitates precise control of P, N content in the product, it being understood that the molar ratio can also be 1:20, 1:40, 1:60, 1:80, 1:100, 1:120, and any point within this range.

In a preferred embodiment, the amino-terminated polyamidoamine dendrimer is selected from at least one of the group consisting of G0-G5 dendrimers. This solution specifically defines the type of the amino-terminated polyamidoamine dendrimer because the amino-terminated polyamidoamine dendrimer has a high nitrogen content and the nitrogen content increases proportionally with the increase of the number of generations.

In a preferred embodiment, the phosphorus-containing compound is selected from at least one of phosphoric acid, tributyl phosphate, hydroxyethylidene diphosphonic acid, chlorophosphate, diphenyl phosphate, ethylenediamine tetramethylene phosphonic acid, triethyl phosphate, polyaminopolyether methylene phosphonic acid, 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, aminotrimethylene phosphonic acid, diethylenetriamine pentamethylene phosphonic acid, bis 1, 6-hexylidene triamine pentamethylene phosphonic acid. The technical solution defines in particular the type of phosphorus-containing compound, it being understood that the phosphorus-containing compound may also be another substance reasonably selected by the person skilled in the art in combination with the general knowledge in the art.

In a preferred embodiment, the acid scavenger is at least one selected from diethylamine, triethylamine, pyridine, sodium bicarbonate, sodium carbonate and sodium hydroxide; the solvent is at least one selected from chloroform, N-dimethylformamide, N-dimethylacetamide, diethyl ether, methanol, ethanol, isopropanol, tetrahydrofuran, acetonitrile, dimethyl sulfoxide and dichloromethane. The technical scheme specifically limits the types of the acid-binding agent and the solvent, and the acid-binding agent and the solvent are all the most common commercial monomers or solvents in the market and have proper price, and it can be understood that the acid-binding agent and the solvent can also be other substances reasonably selected by a person skilled in the art in combination with common knowledge in the field. In the embodiment, commercial monomers on the market are directly used as raw materials, the dendritic compound with high nitrogen and phosphorus content is prepared through simple chemical reaction of amino and phosphate groups, the reaction period is short, the production process is simple, the cost is low, and the industrial large-scale production can be met. The dendritic compound with high nitrogen and phosphorus content prepared by the embodiment perfectly keeps the dendritic structure and accurately controls the P, N content, and can be widely applied to flame retardants.

The invention also provides a dendritic nitrogen-phosphorus compound prepared by any one of the preparation methods. The dendritic nitrogen-phosphorus compound has the following formula, has high nitrogen content and a specific N/P ratio.

In a preferred embodiment, the mass fraction of phosphorus in the dendritic nitrogen-phosphorus compound is 8.5% -14.6%, and the mass fraction of nitrogen is 39.8% -47%. The technical scheme specifically limits the phosphorus content and the nitrogen content in the dendritic nitrogen-phosphorus compound, and it needs to be explained that the general theoretical phosphorus content of the organic phosphorus flame retardant is 5.4% -13%; for a high molecular system, the phosphazene novel flame retardant has the best comprehensive performance at present, and the N/P ratio of the existing related products can reach that the phosphorus content (%) is more than or equal to 13.65 and the nitrogen content (%) is more than or equal to 37.5. The dendritic nitrogen-phosphorus compound prepared by the preparation method has the advantages that the mass fraction of phosphorus is 8.5-14.6%, the mass fraction of nitrogen is 39.8-47%, the dendritic nitrogen-phosphorus compound has high nitrogen content, a large amount of nitrogen is generated during combustion due to the high nitrogen content, oxygen is isolated, and the dendritic nitrogen-phosphorus compound has a good flame retardant effect, and can be understood that the phosphorus content can be any point value within the ranges of 9%, 10%, 11%, 12%, 13%, 14%, and 40%, 41%, 42%, 43%, 44%, 45%, 46%, and any point value within the ranges.

In a preferred embodiment, the mass ratio of N/P in the dendritic nitrogen-phosphorus compound is 2.7-5.5: 1. The technical scheme further limits the proportion of N/P in the dendritic nitrogen-phosphorus compound, and is characterized in that although high nitrogen content generates a large amount of nitrogen during combustion, so that oxygen is isolated, and the dendritic nitrogen-phosphorus compound has a good flame retardant effect, the flame retardant effect is better if the proportion of N/P is higher, the technical scheme particularly limits the mass ratio of N/P in the dendritic nitrogen-phosphorus compound to be 2.7-5.5:1, and the dendritic nitrogen-phosphorus compound has a good flame retardant effect within the range. It is understood that the ratio may also be 3:1, 4:1, 5:1, and any point ratio within the range thereof.

In recent years, with the development of flame retardant materials and the rapid expansion of market demands, flame retardants having high efficiency, environmental friendliness, and versatility have attracted more and more attention. With the increasing requirements of human beings on environmental protection and health and the emergence of regulations for limiting and prohibiting the use of halogen flame retardants, halogen flame retardants widely used in the market face a great challenge. The restriction of halogen flame retardants by domestic and foreign laws and regulations has made the demand for halogen-free flame retardants increasingly strong. The halogen-free flame retardant is mainly divided into two major classes, organic and inorganic, based on the phosphorus nitrogen system. Generally, inorganic flame retardants usually need relatively high amounts of the inorganic flame retardants to exert the effects, the flame retardant effect of the organic phosphorus flame retardants is closely related to the phosphorus content, sufficient organic phosphorus flame retardants need to be added to achieve the desired flame retardant efficiency, and the increase of the addition amount is accompanied by the decrease of other properties, so the high-phosphorus flame retardants with low addition amount become the research direction. The nitrogen-phosphorus flame retardant is used as a halogen-free intumescent flame retardant, is widely applied to flame retardant modified polymers along with the rise of flame retardant technology, and the polymer containing nitrogen and phosphorus elements has good thermal stability and flame retardance and has the following advantages as a flame retardant: (1) after the chlorine atoms are substituted by the halogen-free groups, the halogen-free halogen free flame retardant rubber composition is free flame retardant flame; (2) the flame retardant is rich in N, P two elements, and has high synergistic flame retardant efficiency; (3) strong reactivity, easy functional modification and various types. Therefore, the nitrogen-phosphorus polymer has good market prospect as a flame retardant and is a perfect substitute product of a halogen flame retardant. When the nitrogen and phosphorus polymer is heated, a uniform carbon foam layer can be generated on the surface of the nitrogen and phosphorus polymer, so that the nitrogen and phosphorus polymer has the functions of heat insulation, oxygen isolation and smoke suppression, and prevents the generation of molten drop, thereby having good flame retardant property.

The nitrogen-phosphorus flame retardant belongs to an intumescent flame retardant, which is a very enthusiastic flame retardant in the current market and belongs to a halogen-free flame retardant. An acid source (a dehydrating agent or a carbonization accelerant), an air source (a foaming agent or a nitrogen source) and a carbon source (a carbonizing agent) are the most basic three components, wherein the acid source comprises phosphorus-containing elements such as ammonium polyphosphate, phosphate ester and the like; common gas sources are generally melamine, polyamide and other nitrogen-containing substances; the carbon source can form the skeleton of the carbon layer and is a polyhydroxy compound containing a large amount of carbon elements, such as a phenol resin, an organic resin containing hydroxyl groups, and the like. The quality of the flame retardant effect mainly depends on the stability of the generated carbon layer and the barrier effect, and the barrier effect is mainly embodied in the insulation of internal combustible gas and external oxygen and heat. The carbon layer formation process is as follows: the acid source can generate acid serving as a dehydrating agent under the heating condition, then the generated acid is esterified with the carbon source, and the esterification reaction can be accelerated by a large amount of amino groups contained in the foaming source, so that ester crosslinking is promoted to form carbon finally; during the reaction, a large amount of non-combustible gas is generated, and the gas can foam a system which is in a molten state in the esterification reaction, at the moment, the carbon forming agent and the formed ester are dehydrated to form inorganic matters and carbon residues, and the system is further foamed; when the reaction is about to be finished, the system can be gelled and solidified, and a foam carbonization layer is finally formed, so that heat is difficult to penetrate through a condensed phase, oxygen is effectively prevented from entering a combustion area, and further combustion decomposition of the material is prevented. In the nitrogen-phosphorus flame retardant in the dendritic nitrogen-phosphorus compound provided by the embodiment, the nitrogen element and the phosphorus element are synergistic, so that a good condensed phase carbonization effect can be achieved, but the condensed phase carbonization effect of the system is reduced due to the excessively high phosphorus content. The technical scheme specifically limits the mass ratio of N/P to 2.7-5.5:1, the flame retardant effect is good within the modification range, and the dendritic nitrogen-phosphorus polymer can accurately control the molecular structure so as to accurately control the content of P, N, and has more excellent structure and flame retardant effect.

The invention also provides application of the dendritic nitrogen-phosphorus compound in a flame retardant. When the dendritic nitrogen-phosphorus compound is used as a flame retardant, a large amount of nitrogen is generated during combustion due to high nitrogen content, so that oxygen is isolated, and the dendritic nitrogen-phosphorus compound has a good flame retardant effect.

The invention also provides a flame retardant which comprises the dendritic nitrogen-phosphorus compound. The dendritic nitrogen-phosphorus compound prepared by the invention perfectly maintains the dendritic structure and accurately controls the P, N content, and contains a large amount of hydroxyl. Meanwhile, the polymer can play a role of a carbon source, and development of a halogen-free, non-toxic, environment-friendly and efficient flame retardant based on the dendritic nitrogen-phosphorus compound with the flame retardant property is greatly promoted.

In order to more clearly and specifically describe the dendritic nitrogen-phosphorus flame retardant, the preparation method, the application and the flame retardant provided by the embodiment of the invention, the following description will be given with reference to specific embodiments.

Example 1

Adding 0.1mol of G2 PAMAM in a reaction bottle, dissolving in methanol, adding 0.8mol of H₃PO₃Excess sodium bicarbonate was added. Starting mechanical stirring, placing in an oil bath pan, and heating the oil bath to 60 ℃. The reaction was refluxed by condensation for 6 hours. Washing the product with deionized water to neutrality, and vacuum distilling and drying to obtain the purified dendritic nitrogen-phosphorus compound 1 with a yield of 83%.

Example 2

0.1mol of G2 PAMAM is added into a reaction bottle and dissolved in methanol, 0.2mol of ethylenediamine tetramethylene phosphonic acid is added, and triethylamine is added. Starting mechanical stirring, placing in an oil bath pan, and heating the oil bath to 40 ℃. The reaction was refluxed for 2 hours. Washing the product with deionized water to neutrality, and vacuum distilling and drying to obtain the purified dendritic nitrogen-phosphorus compound 2 with yield of 97%.

Example 3

0.1mol of G1 PAMAM is added into a reaction bottle and dissolved in ethanol, 0.1mol of hydroxyethylidene diphosphonic acid is added, and triethylamine is added. Starting mechanical stirring, placing in an oil bath pan, and heating the oil bath to 50 ℃. The reaction was refluxed by condensation for 4 hours. Washing the product with deionized water to neutrality, and vacuum distilling and drying to obtain the purified dendritic nitrogen-phosphorus compound 3 with yield of 94%.

Example 4

0.1mol of G1 PAMAM is added into a reaction bottle and dissolved in N, N-dimethylformamide, 0.4mol of 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is added, and triethylamine is added. Starting mechanical stirring, placing in an oil bath pan, and heating the oil bath to 60 ℃. The reaction was refluxed for 2 hours. Washing the product with deionized water to neutrality, and vacuum distilling and drying to obtain the purified dendritic nitrogen-phosphorus compound 4 with yield of 94%.

Example 5

0.1mol of G3 PAMAM was added to the reaction flask and dissolved in N, N-dimethylformamide, 0.6mol of diphenyl phosphate was added, and sodium carbonate was added. Starting mechanical stirring, placing in an oil bath pan, and heating the oil bath to 60 ℃. The reaction was refluxed by condensation for 8 hours. Washing the product with deionized water to neutrality, and vacuum distilling and drying to obtain the purified dendritic nitrogen-phosphorus compound 5 with yield of 82%.

Example 6

A flame retardant comprising the following components: the content of the dendritic nitrogen-phosphorus compound 1 is 5 percent, and the content of the polybutylene terephthalate is 95 percent. The component contents are counted in mass percent. The flame-retardant test results show that the flame is extinguished within 7 seconds and drips exist.

Example 7

A flame retardant comprising the following components: the content of the dendritic nitrogen-phosphorus compound 2 is 5 percent, and the content of the polybutylene terephthalate is 95 percent. The component contents are counted in mass percent. The flame-retardant test results show that the flame is extinguished within 5 seconds and no drips exist.

Example 8

A flame retardant comprising the following components: the content of the dendritic nitrogen-phosphorus compound 3 is 5 percent, and the content of the polybutylene terephthalate is 95 percent. The component contents are counted in mass percent. The flame-retardant test results show that the flame is extinguished within 4 seconds and no drips exist.

Example 9

A flame retardant comprising the following components: the content of the dendritic nitrogen-phosphorus compound 4 is 5 percent, and the content of the polybutylene terephthalate is 95 percent. The component contents are counted in mass percent. The flame-retardant test results show that the flame is extinguished within 5 seconds and no drips exist.

Example 10

A flame retardant comprising the following components: 5 percent of dendritic nitrogen phosphorus compound and 95 percent of polybutylene terephthalate. The component contents are counted in mass percent. The flame-retardant test results show that the flame is extinguished within 6 seconds and drips exist.

Comparative example 1

The experiment was carried out using pure PBT as a comparative example.

TABLE 1 comparison of flame retardant Properties of flame retardants at different addition levels of PA and PBT

Performance testing

After pelletizing and drying examples 6-10 and comparative examples, the limiting oxygen index LOI, the vertical burning UL-94 rating and the tensile and notched impact strengths were determined and the results are shown in Table 2.

TABLE 2 Performance testing of the halogen-free intumescent flame retardant prepared in the example in PBT composite Material