Fire fighters for the safety of people's production of property: flame retardants

In the summer heat and heat, electronic appliances can easily cause fire, and the large amount of wood furniture, plastic decoration materials and textiles are also flammable objects in the room. If there is no protection from flame retardants, fire hazards will be everywhere.

But for most people, "what is a flame retardant?" is not something they care about. Because people don't see it at all, they don't know it exists. In modern life, however, flame retardants are almost everywhere. In we carry mobile phones, computer desk, ride the subway every day, driving a car, or even allow you to sleep every night in the mattress, tens of thousands of small guards of the flame retardant molecular is like an alert as ready, silent guard your life safety and property safety, let us away from the threat of fire.

A wide variety of families

What is flame retardant? As the name suggests, the flame retardant is able to prevent burning of chemical agents, flame retardant is added in the flammable material, can make the material in difficult to ignite, in case of fire or easily after lighting the flame spreading, it is not easy. Flame retardants can also reduce heat and reduce flue gas release.

Flame retardants is not simply a product, but a large family, members of the family of 700 ~ 800, can be divided into organic flame retardants and inorganic flame retardants, or according to the response elements are divided into halogen, phosphorus, nitrogen and silicon, can also according to the using method is divided into hybrid, add type and reaction type.

There are so many types of flame retardants to satisfy the "taste" of different materials. Each flame retardant guard has his or her best position, and they can be used together, work together, and work well to prevent fire.

These invisible little guardians are active in every aspect of their lives. They quietly lurking in the mobile phone, computer, TV, refrigerator, etc all kinds of electronic circuit boards, all kinds of electronic products in the plastic shell and without them, plane, ship, bus seats and have their lives in building external wall thermal insulation material. In developed countries such as Europe and the United States, flame retardants are widely used in clothing for children, elderly people and patients. Our country also introduced national standard, to building material and public place use adornment, textile, furniture, electric wire, switch, lamps and lanterns, home appliance and so on make clear flame retardant requirement.

The flame retardant principle is different

It is not easy to bear the burden of the fire safety guard, and the flame retardants must have a hard skill.

Combustion requires three major elements - combustible, combustible (oxygen) and source of ignition. The combustion process is divided into heating, decomposition, fire, combustion and spread. If you remove any of these elements, or try to control the burning process in the bud of heating and decomposition, you can effectively avoid fire.

In the case of flame burning, different types of flame retardants have their own high measures: some can prevent flammable gas from being produced by absorbing heat; Some form a dense covering layer on the surface of the combustible, isolating the contact between combustible and oxygen. Some of them capture the free radicals that participate in the combustion reaction, and achieve the goal of inhibiting radical chain reaction. There is also the effect of slowing the rate of combustion by producing a non-flammable gas to dilute oxygen.

Inorganic flame retardants Al (OH) 3 will break down after heated to 200 ℃, release water of crystallization and crystallization water evaporate into water vapor heated. This series of processes will absorb a large amount of heat, reducing the temperature of the material's surface and flame area, and slowing down the rate of pyrolysis reaction. In addition, the water vapor produced by the crystallographic water also reduces the concentration of oxygen and further inhibits the spread of the fire.

Phosphorus flame retardant heat becomes more stable crosslinking structure of solid matter or carbide layer, just like a solid layer of armor, the fuel, which can prevent further pyrolysis materials, also can prevent material internal decomposition of burning combustible gas overflow.

Bromide flame retardants in the evaporation temperature and decomposition temperature of the polymer materials is the same or similar, when polymer thermal decomposition, bromine flame retardants will be volatile, and thermal decomposition product at the same time into the gas phase combustion zone. The flame retardant can quickly capture the free radicals in the combustion zone of the gas phase, inhibit the free radical chain reaction, stop the flame propagation, and eventually slow down the combustion reaction speed until the end.

In short, each flame retardant has its own secret.

Extend the fire escape time

As usual there is no fire, people is hard to see the figure of firefighters, and only at the scene of the fire, flame retardant can show the hero, this is most obvious in the aviation field. In order to prevent fire from happening, the most stringent flame retardant standards have been adopted on the aircraft.

As early as 30 years ago, the federal aviation administration (FAA) investigation found that the best way to reduce fire casualties on a plane was to extend escape time. If you use flame retardant materials in the seats, carpets and luggage, you can reduce the fire rate and provide passengers with a long escape. At the moment, advances in flame retardants have been able to extend people's escape from the fire scene from two minutes to 20 minutes. According to the commission's assessment, the number of European fire deaths has fallen by 20 per cent over the past decade as a result of widespread use of flame retardants.

In the 2005 air France crash in Toronto, flame retardant materials saved 309 passengers. In 2013, in the crash of asiana airlines in San Francisco, the flame retardant material helped 304 people to evacuate safely. In July 2015, a man from shenzhen airlines set fire to the plane, attempting to ignite the plane seat attempt.

Especially in the asiana, in the air crash accident in the high flame temperature to put metal flashing, but the cabin seats, carpets and luggage without burning, escape to the success of more than 300 passengers. Several accidents have seen the power of the flame retardants.

Once there is no fire retardant, the fire situation is completely different. The fire at the glenfield building in the Chelsea district of kensington, London, has killed almost 79 people in a 24-story apartment building. In 2009, a fire broke out in the building of CCTV, because the wet materials did not meet the flame retardant standards, and the fire was difficult to extinguish, resulting in an economic loss of 160 million yuan. And Shanghai jing 'an district 2010 teachers, 2011 shenyang royal hotel apartment fire accidents such as fire, is because of exterior wall thermal insulation material is missing in the flame retardant, fire is so wild.

Without the protection of the flame retardant, the TV will soon be ignited by fire and can be consumed by fire in two minutes. If such a TV set catches fire in the room, a flashover will occur in less than five minutes. What is the flashover is 600 ℃ high temperature in the room, all of the items and burns in a flash. Once you have a flashback, it's almost impossible to escape.

Not all bromine systems are harmful

Although the flame retardants are devoted and devoted to protecting human beings from fire hazards, there are occasional finicky and rebuked ones. In recent years, some environmentalists have argued that bromine flame retardants can harm the environment and human health. For such question, flame retardant materials expert, professor at the university of Beijing institute of technology, the Chinese society of these flame retardants branch secretary Zhou Zhengmao says, this kind of view is biased misunderstanding, lack of scientific basis.

Zhou Zhengmao says, bromine flame retardants in the family has more than 80 varieties, harmful to human health and the environment of bromine flame retardant is just individual varieties, such as five of pbdes pbdes and eight pbdes were included in the list of "Stockholm convention on persistent organic pollutants. But the two types of flame retardants have long been "in the past" and were banned more than a decade ago. Our country has never produced bbbdiphenyl ether, and pentabromodiphenyl ether has been discontinued since 2004. It is also irresponsible to confuse individual breeds with other highly effective, non-toxic brominated flame retardants.

As a chemical, the flame retardants are carefully evaluated before they are put into market to ensure their safety, Mr Zhou said. So far, the European Union all flame retardants risk assessment results show that the flame retardant used in the consumer goods will not cause a harm to human health, do not have any existing medical report of human disease associated with flame retardants.

In addition, now worldwide for chemicals regulation is more and more strict, and flame retardant at home and abroad related laws and regulations have continued to improve, poisonous and harmful flame retardants have been eliminated, green environmental protection, not easily absorbed by organism of macromolecular polymer flame retardant agent is becoming the development direction of the future. As a new force in the fire, they will increasingly take on the task of ensuring the safety of life and property.