TW202405138A - Liquid crystal polymer composite material, flame-retardant material and preparation method thereof - Google Patents

Abstract

The invention particularly relates to a liquid crystal polymer composite material, a flame-retardant material and a preparation method of the flame-retardant material, and belongs to the technical field of high polymer materials. The phosphorus-doped and modified piperazine, cyanuric chloride and trichloromethane are subjected to a reaction, and the phosphorus-containing triazine charring agent is obtained; the preparation method comprises the following steps: reacting a phosphorus-containing triazine charring agent, dimethyl sulfoxide and an acid source to obtain a flame-retardant material; wherein the acid source contains hydroxyl and is used for carrying out self-condensation reaction with the phosphorus-containing triazine charring agent; phosphorus-doped and modified piperazine is grafted to cyanuric chloride to obtain a phosphorus-containing triazine charring agent, so that the charring rate of the phosphorus-containing triazine charring agent is increased, the phosphorus-containing triazine charring agent is more completely coated on the surface of a matrix to play a role in oxygen insulation and heat insulation, the phosphorus-containing triazine charring agent and hydroxyl of an acid source are subjected to a self-condensation reaction to form a flame-retardant material, and the flame-retardant material has a good flame-retardant effect. The phenomenon that the flame retardant is non-uniformly dispersed in the matrix due to non-uniform mixing is overcome, so that the flame-retardant effect is more stable, and the problem of poor flame-retardant effect of the flame-retardant material is solved.

Description

Liquid crystal polymer composite materials, flame retardant materials and preparation methods thereof

The invention belongs to the technical field of polymer materials, and particularly relates to a liquid crystal polymer composite material, a flame retardant material and a preparation method thereof.

Liquid crystal polymer (LCP) is a polymer between solid and liquid and a new type of polymer material. Its high strength, high modulus, heat resistance and other advantages make it have broad application prospects in many fields such as electronic parts, home appliances and automobile parts. However, while polymer materials bring convenience to life, they also increase great safety risks. Most polymer materials can be burned, and the toxic gases and large amounts of smoke produced during combustion will further harm humans. Health and ecological environment, the resulting problems often attract worldwide attention. Liquid crystal polymers also have such problems to a certain extent. Therefore, LCP needs to be modified to inhibit or prevent its chemical reactions during the combustion process, so as to delay or even stop the spread of flames, thus broadening the application fields of LCP.

The flame retardancy of polymer materials can be divided into two methods: intrinsic flame retardancy and additive flame retardancy. The former is to add flame retardant elements such as phosphorus, nitrogen, and silicon to the polymer molecular chain through chemical methods, thereby reducing its combustion performance. , to achieve the flame retardant effect, the latter refers to adding flame retardant to the material through physical blending, thereby improving the flame retardant performance of the composite material.

Additive flame retardants can be divided into two categories: halogen flame retardant and halogen-free flame retardant. Since halogen flame retardant composite materials will produce a large amount of toxic smoke during the combustion process, it poses a threat to people's lives; halogen-free flame retardant It can also be divided into magnesium-aluminum flame retardants, phosphorus-based, nitrogen-based, silicon-based and intumescent flame retardants. Magnesium-aluminum flame retardants mainly absorb a large amount of heat when they are thermally decomposed to reduce the temperature of the combustion system, and the glass/ceramic layer produced by its decomposition covers the surface of the polymer to block the spread of oxygen, heat and combustibles; Phosphorus-based flame retardants mainly produce phosphoric acid through their decomposition at high temperatures, which are further condensed into pyrophosphoric acid and water under sufficient heat; nitrogen-based flame retardants such as melamine decompose at high temperatures and deaminate, reducing the amount of flammable gases. concentration and can generate stable condensed products; silicone flame retardants can flame retard polymers in the gas phase and solid phase at the same time, effectively reduce the heat release of the polymer, and can reflect thermal radiation; intumescent flame retardants ( IFR) is a single/multi-component flame retardant composed of acid source, carbon source and core. During the heating process, the acid source is decomposed into inorganic acid mainly phosphoric acid under the influence of high temperature, and the inorganic acid plays a role in the formation of the carbon layer. The catalytic effect causes the dehydration reaction between the carbon source and the polymer matrix to form; at the same time, the pyrolysis of the gas source produces ammonia, water vapor and other gases, which foam during the carbonization process and expand the carbon layer, which is coated in the protected The surface of the matrix acts as a barrier to insulate oxygen and heat, preventing further cracking of the polymer matrix; at the same time, the carbon layer also prevents internal flammable volatiles from spreading to the outside.

Among halogen-free flame retardants, magnesium-aluminum flame retardants have the advantages of being green, environmentally friendly, widely sourced, and low-priced. However, their flame retardant efficiency is relatively poor. The amount added to the polymer is too large, which affects the mechanical properties of the flame retardant material. The serious decline has limited its application in many fields; there are many types of phosphorus flame retardants, and the variety is complete, which has greatly promoted the development of flame retardants in the direction of halogen-free and environmental protection. However, phosphorus flame retardants not only depend on their own physical and chemical properties Performance also depends on the surrounding chemical environment during pyrolysis; nitrogen-based flame retardants have the advantages of low smoke and low (non-)toxicity. Polymers containing nitrogen-based flame retardants are also easier to recycle, but they are used alone The efficiency is low, and it is usually used in conjunction with other flame retardants; silicone flame retardants do not have any side effects on the environment, are green and environmentally friendly, and need to be modified to improve their flame retardant properties; intumescent flame retardants have The advantages of high flame retardant efficiency, low smoke, low (non)toxicity and resistance to melt dripping make its market prospects broader.

The purpose of the present invention is to provide a liquid crystal polymer composite material, a flame retardant material and a preparation method thereof, so as to solve the problem of poor flame retardant effect of current flame retardant materials.

Embodiments of the present invention provide a method for preparing flame retardant materials. The method includes:

Phosphorus doping modification of piperazine;

React phosphorus-doped modified piperazine, cyanuric chloride and chloroform to obtain a phosphorus-containing triazine carbon-forming agent;

React the phosphorus-containing triazine carbonizer, dimethyl sulfoxide and an acid source to obtain a flame retardant material;

Wherein, the acid source contains a hydroxyl group for self-condensation reaction with the phosphorus-containing triazine carbon-forming agent.

Optionally, the phosphorus doping modification of piperazine specifically includes:

Combine the modifier, formaldehyde solution and solvent to obtain a modified solution;

Mixing the modification solution and the piperazine solution to perform phosphorus doping modification on the piperazine;

Wherein, the modifier is a phosphorus-containing substance.

Optionally, the phosphorus-containing substance includes phosphorous acid and/or hypophosphorous acid.

Optionally, the phosphorus-doped modified piperazine, cyanuric chloride and chloroform are reacted to obtain a phosphorus-containing triazine carbon-forming agent, which specifically includes:

Mix cyanuric chloride and chloroform, and then add the phosphorus-doped and modified piperazine for reaction to obtain a phosphorus-containing triazine carbon-forming agent;

Wherein, the pH value of the reaction is controlled to be 7-8.

Optionally, the piperazine modified by phosphorus doping is added three times, namely the first addition, the second addition and the third addition, and the reaction temperature of the first addition is 0-5°C. , the reaction temperature of the second addition is 45-55°C, and the reaction temperature of the third addition is 85-95°C.

Optionally, the acid source is a silane modified acid source.

Optionally, the preparation method of the silane modified acid source includes:

Mix the acid source, emulsifier OP-10, boric acid and diethylene glycol dimethyl ether to obtain the system to be modified;

The system to be modified and the silane coupling agent are mixed and reacted to obtain a silane modified acid source.

Optionally, the acid source includes at least one of ammonium polyphosphate, melamine phosphate and melamine polyphosphate.

Based on the same inventive concept, embodiments of the present invention also provide a flame retardant material, which is produced by the method as described above.

Based on the same inventive concept, embodiments of the present invention also provide a liquid crystal polymer composite material. The components of the composite material include a liquid crystal polymer and a flame retardant material as described above.

One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

In the preparation method of the flame retardant material provided by the embodiment of the present invention, piperazine modified by phosphorus doping is grafted onto cyanuric chloride to obtain a phosphorus-containing triazine carbon-forming agent to increase its char-forming rate and make it More completely coated on the surface of the substrate, it plays the role of oxygen and heat insulation. The phosphorus-containing triazine carbon-forming agent and the hydroxyl group of the acid source are used to perform a self-condensation reaction to form a flame retardant material, which overcomes the problem of uneven mixing. The phenomenon of uneven dispersion in the matrix makes the flame retardant effect more stable and solves the problem of poor flame retardant effect of current flame retardant materials.

The above description is only an overview of the technical solution of the present invention. In order to have a clearer understanding of the technical means of the present invention, it can be implemented according to the content of the description, and in order to make the above and other objects, features and advantages of the present invention more obvious and understandable. , the specific embodiments of the present invention are listed below.

The present invention will be described in detail below with reference to specific implementation modes and examples, from which the advantages and various effects of the present invention will be more clearly presented. Those skilled in the art should understand that these specific implementation modes and examples are used to illustrate the present invention, but not to limit the present invention.

Throughout this specification, unless otherwise specifically stated, the terms used herein are to be understood as having the meaning commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. If there is any conflict, this manual takes precedence.

Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased in the market or prepared by existing methods.

The technical solutions of the embodiments of this application are to solve the above technical problems. The general idea is as follows:

According to a typical embodiment of the present invention, a method for preparing flame retardant materials is provided, which method includes:

Step S1. Perform phosphorus doping modification on piperazine;

In some embodiments, the phosphorus doping modification of piperazine specifically includes:

Combine the modifier, formaldehyde solution and solvent to obtain a modified solution;

Mixing the modification solution and the piperazine solution to perform phosphorus doping modification on the piperazine;

Wherein, the modifier is a phosphorus-containing substance.

Further, the phosphorus-containing substance includes phosphorous acid and/or hypophosphorous acid.

Specifically, in this embodiment, a certain quality of modifier, formaldehyde solution and deionized water are added to a three-necked flask, and after sufficient stirring, the pre-dissolved aqueous solution of piperazine is added to the reaction system at a certain temperature, and then The reaction temperature rises to a certain temperature, and after several hours of reaction, it is washed and filtered three times with deionized water to obtain phosphorus-doped modified piperazine;

Step S2. React the phosphorus-doped modified piperazine, cyanuric chloride and chloroform to obtain a phosphorus-containing triazine carbon-forming agent;

In some embodiments, the phosphorus-doped modified piperazine, cyanuric chloride and chloroform are reacted to obtain a phosphorus-containing triazine carbon-forming agent, which specifically includes:

Mix cyanuric chloride and chloroform, and then add the phosphorus-doped and modified piperazine for reaction to obtain a phosphorus-containing triazine carbon-forming agent;

Wherein, the pH value of the reaction is controlled to be 7-8.

In actual operation, the pH value of the reaction can be controlled to 7-8 by adding sodium hydroxide solution. The sodium hydroxide solution is sodium hydroxide solvent in deionized water. In this embodiment, sodium hydroxide The quality ratio to deionized water is 1:8.

Furthermore, the number of additions of the phosphorus-doped modified piperazine is three times, namely the first addition, the second addition and the third addition, and the reaction temperature of the first addition is 0-5°C. , the reaction temperature of the second addition is 45-55°C, and the reaction temperature of the third addition is 85-95°C.

Specifically, in this embodiment, a certain quality of cyanuric chloride and chloroform were added to a three-necked flask, stirred to fully dissolve, and then the reaction was placed in an ice bath, and then a certain quality of cyanuric chloride was added in three times. Hetero-modified piperazine, the first reaction temperature was 0°C, the second reaction temperature was 50°C, and the third reaction temperature was 90°C. The pH value of the entire reaction system was always maintained at 7 by adding sodium hydroxide solution to the system. -8. After liquid separation, remove the lower layer solution and spin evaporate it, then wash it with water to obtain a phosphorus-containing triazine carbon-forming agent.

Step S3. React the phosphorus-containing triazines char-forming agent, dimethyl sulfoxide and an acid source to obtain a flame retardant material; the acid source contains hydroxyl groups for reacting with the phosphorus-containing triazines char-forming agent A self-condensation reaction occurs.

Specifically, in this example, a certain quality of anhydrous dimethyl sulfoxide, a phosphorus-containing triazine carbon-forming agent and a silane-modified acid source were weighed into a three-necked flask, and then reacted at a certain temperature for several hours. , then washed, filtered, and dried to obtain flame retardant materials.

In some embodiments, the acid source is a silane-modified acid source; the preparation method of the silane-modified acid source includes:

Step S0.1. Mix the acid source, emulsifier OP-10, boric acid and diethylene glycol dimethyl ether to obtain the system to be modified;

Step S0.2. Mix the system to be modified and the silane coupling agent to react to obtain a silane modified acid source.

Wherein, the acid source includes at least one of ammonium polyphosphate, melamine phosphate and melamine polyphosphate.

Specifically, in this embodiment, a certain quality of acid source, emulsifier OP-10, boric acid and diethylene glycol dimethyl ether are added to a three-necked flask, and hydrochloric acid is added dropwise under stirring to control the pH value of the solution to 1 -3, then add a certain quality of silane coupling agent uniformly into the three-necked flask at a certain temperature, then raise the reaction temperature to a certain temperature, use rotary evaporation to remove the solvent after several hours of reaction, and finally place the product in a vacuum oven Dry to obtain the silane modified acid source.

According to another typical embodiment of the present invention, a flame retardant material is provided, and the flame retardant material is prepared by the method as described above.

According to another typical embodiment of the present invention, a liquid crystal polymer composite material is provided. The components of the composite material include a liquid crystal polymer and a flame retardant material as described above.

The liquid crystal polymer includes but is not limited to at least one of -HN-Ar-CO-, -O-Ar-CO-, -O-Ar-O-, -HN-Ar-O-, and -HN-Ar-NH-. A fully aromatic liquid crystal polymer, wherein Ar can be selected from at least one of benzene, biphenyl, naphthalene, etc.

The preparation method of the liquid crystal polymer composite material includes: first, drying the liquid crystal polymer and the flame retardant material in an oven for later use. Mix a certain proportion of liquid crystal polymer and flame-retardant material evenly and then extrude and granulate it with an extruder to obtain a flame-retardant liquid crystal polymer-based composite material. The dried liquid crystal polymer composite material is injection molded to obtain the limiting oxygen index (LOI). spline.

The liquid crystal polymer composite material, flame retardant material and preparation method of the present application will be described in detail below with reference to examples, comparative examples and experimental data.

Example 1

A preparation method of liquid crystal polymer composite material, the method includes:

(1) Preparation method of modified carbon-forming agent

Add 15 g of modifier, 12 g of formaldehyde solution and 50 ml of deionized water to a 250 ml three-necked flask. Stir thoroughly and raise the temperature to 70°C. Then add 20 g of the pre-dissolved piperazine aqueous solution. (The mass ratio of piperazine and water is 1:4) was added to the reaction system, then the temperature was raised to 80°C, and the reaction was carried out for 6 hours under stirring. After the reaction was completed, it was washed and filtered three times with deionized water to obtain the phosphorus-doped modification. Sexual piperazine;

Add 14 g of cyanuric chloride and 50 ml of chloroform into a three-necked flask, stir to fully dissolve, then place the reaction in an ice bath, and then add 10 g of phosphorus-doped modified piperazine. Then the aqueous solution of sodium hydroxide was added dropwise. After the addition was completed, the reaction was continued for 6 h. After the reaction was completed, the temperature was raised to 50°C, then 10 g of phosphorus-doped modified piperazine was added, and then the aqueous solution of sodium hydroxide was added dropwise. , continue the reaction for 6 hours after the dropwise addition is completed. After the reaction is completed, the temperature is raised to 90°C, then 10 g of phosphorus-doped modified piperazine is added, and then the aqueous solution of sodium hydroxide is added dropwise. After the dropwise addition is completed, the reaction is continued for 10 h, the pH value of the entire reaction system is always maintained at 7-8. After liquid separation, the lower layer solution is removed, rotary evaporated and washed with water to obtain a phosphorus-containing triazine carbon-forming agent.

(2) Preparation method of modified inorganic phosphorus flame retardant

Add 20 g of melamine polyphosphate, 0.5 g of emulsifier OP-10, 0.6 g of boric acid and 50 ml of diethylene glycol dimethyl ether into a three-necked flask. Add hydrochloric acid dropwise under stirring to control the pH value of the solution: 1-3, then raise the system temperature to 70 ℃, add 6 g of phenyltrimethoxysilane uniformly into the three-necked flask, after the dropwise addition is completed, raise the system temperature to 130 ℃, react for 6 hours and then use rotary evaporator Remove the solvent, and finally dry the product in a vacuum oven at 60°C for 20 h to obtain silane-modified melamine polyphosphate;

(3) Preparation method of flame retardant materials

Weigh 60 ml of anhydrous dimethylsulfoxide, 15 g of phosphorus-containing triazine carbon-forming agent and 10 g of silane-modified melamine polyphosphate into a three-necked flask, and then stir the reaction in an oil bath at 90°C. 12 h, then washed, filtered, and dried to obtain flame retardant materials.

(4) Preparation method of liquid crystal polymer composite materials

First, the liquid crystal polymer and flame retardant materials were dried in a 90°C oven for 12 h before use. Mix 95 parts of liquid crystal polymer and 5 parts of flame retardant material evenly, then extrude and pelletize with an extruder. The plasticizing temperature is 350°C. The melt is pulled out of the die at a speed of 220 mm/s, water-cooled, air-dried, and pelletized. , after drying at 150°C for 4 hours, a flame-retardant liquid crystal polymer matrix composite material was obtained, and the dried liquid crystal polymer composite material was injection molded to obtain an LOI spline.

Example 2

A preparation method of liquid crystal polymer composite material, the method includes:

(1) Preparation method of modified carbon-forming agent

Add 15 g of hypophosphorous acid, 14 g of formaldehyde solution and 50 ml of deionized water to a 250 ml three-necked flask. Stir thoroughly and raise the temperature to 60°C. Then add the pre-dissolved 25 g of piperazine aqueous solution ( The quality ratio of piperazine and water is 1:4) was added to the reaction system, then the temperature was raised to 90°C, and the reaction was carried out for 4 hours under stirring. After the reaction was completed, it was washed and filtered three times with deionized water to obtain the phosphorus doped modification. of piperazine;

Add 10 g of cyanuric chloride and 50 ml of chloroform into a three-necked flask, stir to fully dissolve, then place the reaction in an ice bath, and then add 10 g of phosphorus-doped modified piperazine. Then the aqueous solution of sodium hydroxide was added dropwise. After the dropwise addition, the reaction was continued for 8 h. After the reaction was completed, the temperature was raised to 50°C. Then 10 g of phosphorus-doped modified piperazine was added, and then the aqueous solution of sodium hydroxide was added dropwise. , continue the reaction for 4 hours after the dropwise addition is completed. After the reaction is completed, the temperature is raised to 90°C, then 10 g of phosphorus-doped modified piperazine is added, and then the aqueous solution of sodium hydroxide is added dropwise. After the dropwise addition is completed, the reaction is continued for 10 h, the pH value of the entire reaction system is always maintained at 7-8. After liquid separation, the lower layer solution is removed, rotary evaporated and washed with water to obtain a phosphorus-containing triazine carbon-forming agent.

(2) Preparation method of modified inorganic phosphorus flame retardant

Add 40 g of ammonium polyphosphate, 1 g of emulsifier OP-10, 1.2 g of boric acid and 60 ml of diethylene glycol dimethyl ether into a three-necked flask. Add hydrochloric acid dropwise under stirring to control the pH value of the solution to 1. -3, then raise the system temperature to 70 ℃, add 6 g of ethyltrimethoxysilane uniformly into the three-necked flask, after the dropwise addition is completed, raise the system temperature to 140 ℃, react for 5 hours and remove by rotary evaporation Solvent, and finally place the product in a vacuum oven at 60°C to dry for 12 hours to obtain silane-modified ammonium polyphosphate;

(3) Preparation method of flame retardant materials

Weigh 80 ml of anhydrous dimethyl sulfoxide, 15 g of phosphorus-containing triazine carbon-forming agent and 10 g of silane-modified ammonium polyphosphate into a three-necked flask, then stir and react in an oil bath at 120°C for 10 h, then washing, filtering and drying to obtain flame retardant materials.

(4) Preparation method of liquid crystal polymer composite materials

First, the liquid crystal polymer and flame retardant materials were dried in a 90°C oven for 12 h before use. Mix 90 parts of liquid crystal polymer and 10 parts of flame retardant material evenly, then extrude and pelletize with an extruder. The plasticizing temperature is 310°C. The melt is pulled out of the die at a speed of 220 mm/s, water-cooled, air-dried, and pelletized. , after drying at 150°C for 4 hours, a flame-retardant liquid crystal polymer matrix composite material was obtained, and the dried liquid crystal polymer composite material was injection molded to obtain an LOI spline.

Example 3

A preparation method of liquid crystal polymer composite material, the method includes:

(1) Preparation method of modified carbon-forming agent

Add 15 g of phosphorous acid, 14 g of formaldehyde solution and 50 ml of deionized water to a 250 ml three-necked flask. Stir thoroughly and raise the temperature to 40°C. Then add the pre-dissolved 30 g of piperazine aqueous solution ( The quality ratio of piperazine and water is 1:4) was added to the reaction system, then the temperature was raised to 90°C, and the reaction was carried out for 6 hours under stirring. After the reaction was completed, it was washed and filtered three times with deionized water to obtain the phosphorus doped modification. of piperazine;

Add 12 g of cyanuric chloride and 50 ml of chloroform into a three-necked flask, stir to fully dissolve, then place the reaction in an ice bath, and then add 10 g of phosphorus-doped modified piperazine. Then the aqueous solution of sodium hydroxide was added dropwise. After the dropwise addition was completed, the reaction was continued for 8 h. After the reaction was completed, the temperature was raised to 50°C, then 10 g of phosphorus-doped modified piperazine was added, and then the aqueous solution of sodium hydroxide was added dropwise. , continue the reaction for 6 hours after the dropwise addition is completed. After the reaction is completed, the temperature is raised to 90°C, then 10 g of phosphorus-doped modified piperazine is added, and then the aqueous solution of sodium hydroxide is added dropwise. After the dropwise addition is completed, the reaction is continued for 12 h, the pH value of the entire reaction system is always maintained at 7-8. After liquid separation, the lower layer solution is removed, rotary evaporated and washed with water to obtain a phosphorus-containing triazine carbon-forming agent.

(2) Preparation method of modified inorganic phosphorus flame retardant

Add 30 g of melamine phosphate, 0.8 g of emulsifier OP-10, 1 g of boric acid and 60 ml of diethylene glycol dimethyl ether into a three-necked flask. Add hydrochloric acid dropwise under stirring to control the pH value of the solution to 1. -3, then raise the system temperature to 70°C, drop 8 g of methyltrimethoxysilane into the three-necked flask at a constant speed. After the dropwise addition is completed, raise the system temperature to 130°C, react for 6 hours and remove by rotary evaporation. Solvent, and finally place the product in a vacuum oven at 60°C to dry for 24 hours to obtain silane-modified melamine phosphate;

(3) Preparation method of flame retardant materials

Weigh 50 ml of anhydrous dimethyl sulfoxide, 12 g of phosphorus-containing triazine carbon-forming agent and 10 g of silane-modified melamine phosphate into a three-necked flask, then stir the reaction in an oil bath at 100°C for 10 h, then washing, filtering and drying to obtain flame retardant materials.

(4) Preparation method of liquid crystal polymer composite materials

First, the liquid crystal polymer and flame retardant materials were dried in a 90°C oven for 12 h before use. Mix 85 parts of liquid crystal polymer and 15 parts of flame retardant material evenly, then extrude and pelletize with an extruder. The plasticizing temperature is 320°C. The melt is pulled out of the die at a speed of 220 mm/s, water-cooled, air-dried, and pelletized. , after drying at 150°C for 4 hours, a flame-retardant liquid crystal polymer matrix composite material was obtained, and the dried liquid crystal polymer composite material was injection molded to obtain an LOI spline.

Example 4

A preparation method of liquid crystal polymer composite material, the method includes:

(1) Preparation method of modified carbon-forming agent

Add 12 g of hypophosphorous acid, 10 g of formaldehyde solution and 50 ml of deionized water to a 250 ml three-necked flask. Stir thoroughly and raise the temperature to 50°C. Then add the pre-dissolved 25 g of piperazine aqueous solution ( The quality ratio of piperazine and water is 1:4) was added to the reaction system, then the temperature was raised to 90°C, and the reaction was carried out for 4 hours under stirring. After the reaction was completed, it was washed and filtered three times with deionized water to obtain the phosphorus doped modification. of piperazine;

Add 12 g of cyanuric chloride and 50 ml of chloroform into a three-necked flask, stir to fully dissolve, then place the reaction in an ice bath, and then add 10 g of phosphorus-doped modified piperazine. Then the aqueous solution of sodium hydroxide was added dropwise. After the dropwise addition, the reaction was continued for 6 h. After the reaction was completed, the temperature was raised to 50°C. Then 10 g of phosphorus-doped modified piperazine was added, and then the aqueous solution of sodium hydroxide was added dropwise. , continue the reaction for 6 hours after the dropwise addition is completed. After the reaction is completed, the temperature is raised to 90°C, then 10 g of phosphorus-doped modified piperazine is added, and then the aqueous solution of sodium hydroxide is added dropwise. After the dropwise addition is completed, the reaction is continued for 12 h, the pH value of the entire reaction system is always maintained at 7-8. After liquid separation, the lower layer solution is removed, rotary evaporated and washed with water to obtain a phosphorus-containing triazine carbon-forming agent.

(2) Preparation method of modified inorganic phosphorus flame retardant

Add 40 g of ammonium polyphosphate, 1 g of emulsifier OP-10, 1 g of boric acid and 60 ml of diethylene glycol dimethyl ether into a three-necked flask. Add hydrochloric acid dropwise under stirring to control the pH value of the solution to 1. -3, then raise the system temperature to 70°C, add 6 g of phenyltrimethoxysilane uniformly into the three-necked flask. After the dropwise addition is completed, raise the system temperature to 130°C. After 5 hours of reaction, remove the solvent by rotary evaporation. , and finally the product was dried in a vacuum oven at 60°C for 24 h to obtain silane-modified ammonium polyphosphate;

(3) Preparation method of flame retardant materials

Weigh 60 ml of anhydrous dimethyl sulfoxide, 15 g of phosphorus-containing triazine carbon-forming agent and 10 g of silane-modified ammonium polyphosphate into a three-necked flask, and then stir in an oil bath at 120°C for reaction 6 h, then washing, filtering and drying to obtain flame retardant materials.

(4) Preparation method of liquid crystal polymer composite materials

First, the liquid crystal polymer and flame retardant materials were dried in a 90°C oven for 12 h before use. Mix 80 parts of liquid crystal polymer and 20 parts of intumescent flame retardant evenly, then extrude and granulate with an extruder. The plasticizing temperature is 320°C. The melt is pulled out of the die at a speed of 220 mm/s, cooled with water, and air-dried. , cut into pellets, and dried at 150°C for 4 hours to obtain a flame-retardant liquid crystal polymer-based composite material. The dried liquid crystal polymer composite material was injection molded to obtain an LOI spline.

Example 5

A preparation method of liquid crystal polymer composite material, the method includes:

(1) Preparation method of modified carbon-forming agent

Add 10 g of phosphorous acid, 10 g of formaldehyde solution and 50 ml of deionized water to a 250 ml three-necked flask, stir thoroughly and raise the temperature to 60°C, then add the pre-dissolved 30 g of piperazine aqueous solution ( The quality ratio of piperazine and water is 1:4) was added to the reaction system, then the temperature was raised to 80°C, and the reaction was carried out for 6 hours under stirring. After the reaction was completed, it was washed and filtered three times with deionized water to obtain the phosphorus doped modification. of piperazine;

Add 15 g of cyanuric chloride and 50 ml of chloroform into a three-necked flask, stir to fully dissolve, then place the reaction in an ice bath, and then add 10 g of phosphorus-doped modified piperazine. Then the aqueous solution of sodium hydroxide was added dropwise. After the dropwise addition was completed, the reaction was continued for 7 h. After the reaction was completed, the temperature was raised to 50°C, then 10 g of phosphorus-doped modified piperazine was added, and then the aqueous solution of sodium hydroxide was added dropwise. , continue the reaction for 5 hours after the dropwise addition is completed. After the reaction is completed, the temperature is raised to 90°C, then 10 g of phosphorus-doped modified piperazine is added, and then the aqueous solution of sodium hydroxide is added dropwise. After the dropwise addition is completed, the reaction is continued for 12 h, the pH value of the entire reaction system is always maintained at 7-8. After liquid separation, the lower layer solution is removed, rotary evaporated and washed with water to obtain a phosphorus-containing triazine carbon-forming agent.

(2) Preparation method of modified inorganic phosphorus flame retardant

Add 30 g of melamine polyphosphate, 0.8 g of emulsifier OP-10, 1.2 g of boric acid and 60 ml of diethylene glycol dimethyl ether into a three-necked flask. Add hydrochloric acid dropwise under stirring to control the pH value of the solution: 1-3, then raise the system temperature to 70 ℃, add 6 g of methyltrimethoxysilane dropwise into the three-necked flask at a constant speed. After the dropwise addition is completed, raise the system temperature to 140 ℃, react for 4 hours, and then use rotary evaporation The solvent was removed, and finally the product was dried in a vacuum oven at 60°C for 12 hours to obtain silane-modified melamine polyphosphate;

(3) Preparation method of flame retardant materials

Weigh 80 ml of anhydrous dimethyl sulfoxide, 10 g of phosphorus-containing triazine carbon-forming agent and 8 g of silane-modified melamine polyphosphate into a three-necked flask, and then stir the reaction in an oil bath at 110°C. 8 h, then washed, filtered, and dried to obtain flame retardant materials.

(4) Preparation method of liquid crystal polymer composite materials

First, the liquid crystal polymer and flame retardant materials were dried in a 90°C oven for 12 h before use. Mix 75 parts of liquid crystal polymer and 25 parts of flame retardant material evenly, then extrude and pelletize with an extruder. The plasticizing temperature is 335°C. The melt is pulled out of the die at a speed of 220 mm/s, water-cooled, air-dried, and pelletized. , after drying at 150°C for 4 hours, a flame-retardant liquid crystal polymer matrix composite material was obtained, and the dried liquid crystal polymer composite material was injection molded to obtain an LOI spline.

Comparative example 1

LOI splines were obtained by injection molding using commercially available liquid crystal polymer materials.

Experimental example

The materials provided in Examples 1-5 and Comparative Example 1 were tested for performance, and the results are as shown in the table below. Comparative example 1 Example 1 Example 2 Example 3 Example 4 Example 5 LOI 24-26 28.6 29.4 30.5 32.4 32.7

It can be seen from the above table that the flame retardant performance of the liquid crystal polymer composite material prepared by the method provided in the embodiment of the present application is greatly improved compared with the ordinary liquid crystal polymer material, and the flame retardant effect is better and more stable.

One or more technical solutions in the embodiments of the present invention also have at least the following technical effects or advantages:

(1) The method provided by the embodiment of the present invention grafts phosphorus-doped modified piperazine onto cyanuric chloride to obtain a phosphorus-containing triazine carbon-forming agent to increase its carbon-forming rate and make it more complete. Coated on the surface of the matrix, it plays the role of oxygen and heat insulation. The phosphorus-containing triazine carbon-forming agent and the hydroxyl group of the acid source are used to perform a self-condensation reaction to form a flame retardant material, which overcomes the uneven mixing of the flame retardant in the matrix. The phenomenon of uneven dispersion makes the flame retardant effect more stable.

(2) The liquid crystal polymer composite material provided by the embodiment of the present invention significantly improves the flame retardant performance of the liquid crystal polymer by adding flame retardant materials to the liquid crystal polymer, and the prepared flame retardant liquid crystal polymer composite material does not cause environmental pollution. Small.

Finally, it should be noted that the terms "comprises," "comprising," or any other variation thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements, but also It also includes other elements not expressly listed or that are inherent to the process, method, article or equipment.

Although the preferred embodiments of the present invention have been described, those skilled in the art will be able to make additional changes and modifications to these embodiments once the basic inventive concepts are apparent. Therefore, it is intended that the appended claims be construed to include the preferred embodiments and all changes and modifications that fall within the scope of the invention.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the invention. In this way, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and equivalent technologies, the present invention is also intended to include these modifications and variations.

S1~S3: steps

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, a brief introduction will be made below to the drawings needed to be used in the description of the embodiments. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without exerting creative efforts. Figure 1 is a flow chart of a method provided by an embodiment of the present invention.

S1~S3: steps

Claims (10)

A method for preparing flame retardant materials, wherein the method includes: Phosphorus doping modification of piperazine; React phosphorus-doped modified piperazine, cyanuric chloride and chloroform to obtain a phosphorus-containing triazine carbon-forming agent; React the phosphorus-containing triazine carbonizer, dimethyl sulfoxide and an acid source to obtain a flame retardant material; Wherein, the acid source contains a hydroxyl group for self-condensation reaction with the phosphorus-containing triazine carbon-forming agent. The method for preparing a flame retardant material according to claim 1, wherein the phosphorus doping modification of piperazine specifically includes: Combine the modifier, formaldehyde solution and solvent to obtain a modified solution; Mixing the modification solution and the piperazine solution to perform phosphorus doping modification on the piperazine; Wherein, the modifier is a phosphorus-containing substance. The method for preparing a flame retardant material according to claim 2, wherein the phosphorus-containing substance includes phosphorous acid and/or hypophosphorous acid. The preparation method of flame retardant materials as described in claim 1, wherein the phosphorus-doped modified piperazine, cyanuric chloride and chloroform are reacted to obtain a phosphorus-containing triazine carbon-forming agent, Specifically include: Mix cyanuric chloride and chloroform, and then add the phosphorus-doped and modified piperazine for reaction to obtain a phosphorus-containing triazine carbon-forming agent; Wherein, the pH value of the reaction is controlled to be 7-8. The preparation method of flame retardant materials as described in claim 4, wherein the number of additions of the phosphorus-doped modified piperazine is three times, namely the first addition, the second addition and the third addition, so The reaction temperature of the first addition is 0-5°C, the reaction temperature of the second addition is 45-55°C, and the reaction temperature of the third addition is 85-95°C. The method for preparing a flame retardant material according to claim 1, wherein the acid source is a silane modified acid source. The method for preparing a flame retardant material according to claim 6, wherein the method for preparing the silane modified acid source includes: Mix the acid source, emulsifier OP-10, boric acid and diethylene glycol dimethyl ether to obtain the system to be modified; The system to be modified and the silane coupling agent are mixed and reacted to obtain a silane modified acid source. The method for preparing a flame retardant material according to claim 7, wherein the acid source includes at least one of ammonium polyphosphate, melamine phosphate and melamine polyphosphate. A flame retardant material prepared by the preparation method described in any one of claims 1 to 8. A liquid crystal polymer composite material, the composition of which includes a liquid crystal polymer and a flame retardant material as described in claim 9.

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