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Intumescent flame retardant of epoxy resin fire retardant coatings
2017-11-27 10:58:34
Intumescent flame retardant of epoxy resin fire retardant coatings
This paper describes the selection principle of intumescent flame retardant system and flame retardant for epoxy resin fire retardant coatings.
As the fire retardant coating of epoxy resin, intumescent flame retardant said flame retardant used in epoxy resin coatings in general, with the research of fire retardant coating from non expansive type to the expansion type transition, corresponding fire retardant coating of epoxy resin, intumescent flame retardant from non intumescent system transition to intumescent fire retardant, and entered a steady development stage.
In the research and application of intumescent fire retardant coatings, P - C - N flame retardant system has been basically formed. The system is divided into three parts according to its function, including dehydration catalyst, charring agent and foaming agent.
As a key group of intumescent fire retardant coatings, the main function is to promote the process of dehydration catalyst decomposition and improved coatings, promote the formation of three-dimensional carbon layer structure is not flammable, reduce the production of thermal decomposition of combustible tar, aldehydes and ketones; promote the occurrence of non flammable gas reaction. Ammonium dihydrogen phosphate and ammonium dihydrogen phosphate two were used as dehydration catalysts, but they were eliminated in the late 70s because of their high water solubility and low thermal stability.
Ammonium polyphosphate (APP), magnesium ammonium phosphate and melamine phosphate (MP) are widely used to decompose phosphoric acid and dehydrate polyols. APP is an excellent dehydrating agent. The molecular formula is (NH4) n+2PnO3n+1. It has been proved by IR and 31P NMR that the structure is a chain polymer macromolecule without branched chain.
The experiments show that the salts, esters and amides of phosphoric acid, poly phosphoric acid and so on can be used as dehydration catalysts as long as they decompose at the temperature of 100~value= "250" UnitName= ">250".
In the research and industrial production of fire retardant coatings, the factors such as water solubility, thermal stability, phosphorus content and raw material price should be taken into account, and then the dehydration catalyst should be determined.
When the coating is exposed to flame or high temperature, the carbonization and carbonization of the catalyst form a carbonaceous layer under the action of the catalyst. The effectiveness of the charring agent is mainly determined by its carbon content and the number of hydroxyl groups. The carbon content in the carbonization agent determines its carbonization rate, while the hydroxyl content determines its dehydration and foaming speed.
It is suitable to use high carbon content and low reaction speed as carbonization agent. When using APP as dehydration catalyst, it should adopt the high thermal stability of pentaerythritol (PE) or two (DPE) and pentaerythritol with, or can not form an expanding char ideal; such as the use of starch as a charring agent, before the thermal decomposition of APP, starch has decomposition and produce large amounts of tar, so it cannot the formation of ideal body expansion. In fact, PE is widely used as a charring agent because of the lower price of PE than DPE.
Triphenyl Phosphate (TPP)
Retardants tpp quality standards:
Appearance: white flaky crystal
Content : ≥ 99%;
Acid value (mgKOH / g): ≤ 0.1;
Free phenol : ≤ 0.1%;
Freezing point : ≥ 47.0 ℃
Chromaticity (APHA): ≤ 60;
Moisture : ≤ 0.1%
Density (50 ℃, g/cm3) :1.185-1 .202
Retardants tpp Packing: NW 25KG / composite paper ( lined with black plastic bags ) , a small cabinet loaded 12.5 tons .
Flame retardant TPP has many advantages, such as excellent transparency, softness, bacterial resistance, and water proof, grease-proof, good electric insulation, as well as good compatibility. Flame retardant TPP is mainly used as the flame-retardant plasticizer for cellulose resin, vinyl resin, natural rubber and synthetic rubber. And it may also be used as the flame-retardant plasticizer for glyceryl triacetate thin ester and film, rigid polyurethane foam, phenolic aldehyde resin, and PPO, etc.
Flame retardant TPP is a kind of halogen-free environment-friendly flame retardant with phosphorus element. Most of the products in the market are self-colored flaky crystal, our product is self-colored crystalline powder, and is more soluble in organic solvents. TPP is not soluble in water, but soluble in benzene, chloroform, ether and acetone, and slightly soluble in Z alcohol. Flame retardant TPP is nonflammable with slight aromatic odor and slight deliquescence. The fusion point is about 50 ℃, and fast melts to hoop-shape when heated. The lubricate effect is excellent, and it is often used as the flame retardant plasticize lubricant. What is more, it is used as the flame retardant for many plastics and resins, such as phenolic aldehyde resin, epoxy resin and so on.
This kind of material is decomposed by fire and emits non combustible gas (such as HCl, NH3, H2O, etc.), which makes the coating expand and form spongy carbonaceous layer. Commonly used foaming agents are melamine, dicyandiamide, chlorinated paraffin, etc., and two or more kinds of blowing agents are used in fire retardant coatings, and the effect is better.
For example, the fight with chlorine and phosphorus compounds, not only can be made from solid to gas phase combustion suppression and widely, due to chlorine, phosphorus two elements will have a synergistic effect, the formation of PCl3 and POCl3 compound combustion when they become gas under high temperature, the density ratio of air, can be attached on the substrate the surface covering layer is uniform, the air and fuel are separated, so as to achieve the purpose of inhibiting or preventing combustion.
Generally, melamine (MEL) is the main foaming agent, while chlorinated paraffin (CP) as plasticizer and ammonium polyphosphate (APP) as dehydrating catalyst can also play part of foaming action.
In a word, three kinds of dehydration catalyst, carbonization agent and foaming agent which are composed of intumescent flame retardant system are indispensable. When the coating meets the fire, it firstly softens and melted, and then the foaming agent decomposes and releases the gas, which makes the softening coating swell and increase the volume. At the same time, the dehydration catalyst decomposes and releases the free acid (such as phosphoric acid), so that the polyol (such as pentaerythritol PE) is dehydrated and carbonized, and the charring layer is formed.
This process requires the foaming gas, dehydration catalyst emits phosphoric acid and other substances, these three steps carburetant coordinated dehydration temperature change basically, so that they can produce synergy effect in the expansion process of foaming and fire insulation.
The intumescent fire retardant coatings in general with ammonium polyphosphate (APP) and melamine phosphate (MP) and their combined compound as a flame retardant, water solubility and thermal stability of coating intumescent flame retardant flame retardant properties play an important role, the main difference with the particle size distribution, crystal structure, water soluble the factors and composition of the small differences and so on. The MP produced in the United States and Europe is mainly affected by phosphorus content, thermal stability, water solubility and particle size distribution. By comparing the water solubility of MP and APP, it was found that APP was eventually hydrolyzed into ammonium orthophosphate (AOP), and its water solubility was very low.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
http://www.yaruichem.com
This paper describes the selection principle of intumescent flame retardant system and flame retardant for epoxy resin fire retardant coatings.
As the fire retardant coating of epoxy resin, intumescent flame retardant said flame retardant used in epoxy resin coatings in general, with the research of fire retardant coating from non expansive type to the expansion type transition, corresponding fire retardant coating of epoxy resin, intumescent flame retardant from non intumescent system transition to intumescent fire retardant, and entered a steady development stage.
In the research and application of intumescent fire retardant coatings, P - C - N flame retardant system has been basically formed. The system is divided into three parts according to its function, including dehydration catalyst, charring agent and foaming agent.
As a key group of intumescent fire retardant coatings, the main function is to promote the process of dehydration catalyst decomposition and improved coatings, promote the formation of three-dimensional carbon layer structure is not flammable, reduce the production of thermal decomposition of combustible tar, aldehydes and ketones; promote the occurrence of non flammable gas reaction. Ammonium dihydrogen phosphate and ammonium dihydrogen phosphate two were used as dehydration catalysts, but they were eliminated in the late 70s because of their high water solubility and low thermal stability.
Ammonium polyphosphate (APP), magnesium ammonium phosphate and melamine phosphate (MP) are widely used to decompose phosphoric acid and dehydrate polyols. APP is an excellent dehydrating agent. The molecular formula is (NH4) n+2PnO3n+1. It has been proved by IR and 31P NMR that the structure is a chain polymer macromolecule without branched chain.
The experiments show that the salts, esters and amides of phosphoric acid, poly phosphoric acid and so on can be used as dehydration catalysts as long as they decompose at the temperature of 100~value= "250" UnitName= ">250".
In the research and industrial production of fire retardant coatings, the factors such as water solubility, thermal stability, phosphorus content and raw material price should be taken into account, and then the dehydration catalyst should be determined.
When the coating is exposed to flame or high temperature, the carbonization and carbonization of the catalyst form a carbonaceous layer under the action of the catalyst. The effectiveness of the charring agent is mainly determined by its carbon content and the number of hydroxyl groups. The carbon content in the carbonization agent determines its carbonization rate, while the hydroxyl content determines its dehydration and foaming speed.
It is suitable to use high carbon content and low reaction speed as carbonization agent. When using APP as dehydration catalyst, it should adopt the high thermal stability of pentaerythritol (PE) or two (DPE) and pentaerythritol with, or can not form an expanding char ideal; such as the use of starch as a charring agent, before the thermal decomposition of APP, starch has decomposition and produce large amounts of tar, so it cannot the formation of ideal body expansion. In fact, PE is widely used as a charring agent because of the lower price of PE than DPE.
Triphenyl Phosphate (TPP)
Retardants tpp quality standards:
Appearance: white flaky crystal
Content : ≥ 99%;
Acid value (mgKOH / g): ≤ 0.1;
Free phenol : ≤ 0.1%;
Freezing point : ≥ 47.0 ℃
Chromaticity (APHA): ≤ 60;
Moisture : ≤ 0.1%
Density (50 ℃, g/cm3) :1.185-1 .202
Retardants tpp Packing: NW 25KG / composite paper ( lined with black plastic bags ) , a small cabinet loaded 12.5 tons .
Flame retardant TPP has many advantages, such as excellent transparency, softness, bacterial resistance, and water proof, grease-proof, good electric insulation, as well as good compatibility. Flame retardant TPP is mainly used as the flame-retardant plasticizer for cellulose resin, vinyl resin, natural rubber and synthetic rubber. And it may also be used as the flame-retardant plasticizer for glyceryl triacetate thin ester and film, rigid polyurethane foam, phenolic aldehyde resin, and PPO, etc.
Flame retardant TPP is a kind of halogen-free environment-friendly flame retardant with phosphorus element. Most of the products in the market are self-colored flaky crystal, our product is self-colored crystalline powder, and is more soluble in organic solvents. TPP is not soluble in water, but soluble in benzene, chloroform, ether and acetone, and slightly soluble in Z alcohol. Flame retardant TPP is nonflammable with slight aromatic odor and slight deliquescence. The fusion point is about 50 ℃, and fast melts to hoop-shape when heated. The lubricate effect is excellent, and it is often used as the flame retardant plasticize lubricant. What is more, it is used as the flame retardant for many plastics and resins, such as phenolic aldehyde resin, epoxy resin and so on.
This kind of material is decomposed by fire and emits non combustible gas (such as HCl, NH3, H2O, etc.), which makes the coating expand and form spongy carbonaceous layer. Commonly used foaming agents are melamine, dicyandiamide, chlorinated paraffin, etc., and two or more kinds of blowing agents are used in fire retardant coatings, and the effect is better.
For example, the fight with chlorine and phosphorus compounds, not only can be made from solid to gas phase combustion suppression and widely, due to chlorine, phosphorus two elements will have a synergistic effect, the formation of PCl3 and POCl3 compound combustion when they become gas under high temperature, the density ratio of air, can be attached on the substrate the surface covering layer is uniform, the air and fuel are separated, so as to achieve the purpose of inhibiting or preventing combustion.
Generally, melamine (MEL) is the main foaming agent, while chlorinated paraffin (CP) as plasticizer and ammonium polyphosphate (APP) as dehydrating catalyst can also play part of foaming action.
In a word, three kinds of dehydration catalyst, carbonization agent and foaming agent which are composed of intumescent flame retardant system are indispensable. When the coating meets the fire, it firstly softens and melted, and then the foaming agent decomposes and releases the gas, which makes the softening coating swell and increase the volume. At the same time, the dehydration catalyst decomposes and releases the free acid (such as phosphoric acid), so that the polyol (such as pentaerythritol PE) is dehydrated and carbonized, and the charring layer is formed.
This process requires the foaming gas, dehydration catalyst emits phosphoric acid and other substances, these three steps carburetant coordinated dehydration temperature change basically, so that they can produce synergy effect in the expansion process of foaming and fire insulation.
The intumescent fire retardant coatings in general with ammonium polyphosphate (APP) and melamine phosphate (MP) and their combined compound as a flame retardant, water solubility and thermal stability of coating intumescent flame retardant flame retardant properties play an important role, the main difference with the particle size distribution, crystal structure, water soluble the factors and composition of the small differences and so on. The MP produced in the United States and Europe is mainly affected by phosphorus content, thermal stability, water solubility and particle size distribution. By comparing the water solubility of MP and APP, it was found that APP was eventually hydrolyzed into ammonium orthophosphate (AOP), and its water solubility was very low.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
http://www.yaruichem.com
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