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Will it be feasible to replace halogen-free flame retardants in the future?

来源:荣格塑料 浏览量: Time: 2019-02-18Source : Ringier Plastics Views: Times

The tide of environmental protection is coming. Where does the flame retardant go?

In recent years, the development of polymer materials technology in China has made rapid progress, and the application of various polymer materials has also spread in many fields. Behind the widespread application of polymer materials, many materials have serious fire hazards at the same time. The main reason is that most materials are not easily flame-retardant and easily burn.




The role of flame retardants and multiple systems

The so-called flame retardant, as its name suggests, is a functional additive used to prevent materials from being ignited and to suppress the spread of fire. According to statistics, the global demand for flame retardants in 2017 was approximately 2.85 million tons, of which approximately 1.48 million tons were in North America and Western Europe, approximately 440,000 tons in China, and approximately 760,000 tons in other Asian regions except China. The area is about 170,000 tons. From the perspective of consumption structure, polymer materials such as plastics, rubber, textiles, and coatings are the main bodies that require flame retardancy.

Ye Wen said in an interview with this magazine that flame retardants need to exert endothermic effect, covering effect, inhibit chain transfer effect and non-flammable gas suffocation effect to achieve flame retardant effect. "The purpose of flame retardant is not to not burn at all, but even if it burns, it only releases a small amount of heat, and it burns slowly and releases less toxic smoke, which can greatly increase the escape time."

Ye Chemical's Shanghai Chemical Industry Research Institute Co., Ltd. (hereinafter referred to as “Shanghua Institute”) was founded in 1956 and is the first batch of scientific research institutes in China. Currently, it is mainly engaged in the research and development of new materials, new energy, and new equipment and industry services. . In the field of new materials, the main research contents of Shanghai Chemical Industry Institute include polyolefin catalytic technology, high-performance materials, industrial purification materials, and special functional materials.

The various halogen-free flame retardant technologies are one of the key research contents of the institute and also the main research direction of Ye Wen.

From the general direction, flame retardants are divided into halogenated flame retardants and halogen-free flame retardants, among which halogenated flame retardants easily release toxic fumes and cause pollution to the environment. At present, bromine and chlorine flame retardants are the main ones; Halogen-free flame retardants have the fastest growth rate among flame retardant materials. In recent years, many companies have shown great interest in halogen-free flame retardants. At present, they mainly include inorganic and phosphorus-nitrogen products.

Halogen flame retardants are important varieties of organic flame retardants. Because of their reasonable price, good stability, low addition levels, good compatibility with polymer materials, and the ability to maintain the original properties of flame retardant products, they are It is widely used in many industries. However, its shortcomings are also obvious. A large amount of black smoke and toxic gases are generated during combustion. Once a fire occurs, it will hinder fire fighting and evacuation.

With the increasing awareness of global environmental protection, consumers have higher and higher requirements for flame retardant polymer products, and the application of environmentally-friendly halogen-free flame retardants that are halogen-free, low-smoke and low-toxic has become more and more widespread. According to reports, halogen-free flame retardant additives are mainly phosphorus-nitrogen-based compounds and metal hydroxides. These two types of compounds are non-volatile and do not generate corrosive gases when they are burned. They are known as pollution-free flame retardants, and there is also silicon. Series, boron series and other new types of halogen-free flame retardants.

"Phosphorus-nitrogen-based halogen-free flame retardants have the characteristics of environmental protection and excellent flame-retardant properties, while inorganic-based halogen-free flame retardants are characterized by a large amount of addition, and lack of flame retardancy, processing, and mechanical and physical properties. In summary, at present Halogen-free flame retardants are not as good as halogen flame retardants as a whole, but their performance in terms of safety is sufficient to make up for performance defects! "Ye Wen emphasized.


Under demand, flame retardants usher in rapid development

At present, relevant fire protection regulations and standards in various countries have mandated that the corresponding plastic components in electronic equipment, buildings, and vehicles must meet the corresponding flame retardant and fire protection requirements, which means that flame retardants must be added.

"In fact, at present, all plastics that have contact with the human environment have used flame retardant technology more or less, and the specific difference is nothing more than the level of flame retardant requirements and what kind of flame retardants are used." Ye Wenru said . At present, industries with a large amount of flame retardants in China include wire and cable, home appliances and 3C industries, automobiles, construction, electrical switches, and adhesives.

In many fields of application, especially in residential buildings, the role of flame retardant materials is particularly important. At present, there are more and more high-rise residences. Each building will have a cable well designed like an elevator shaft, connecting various types of cables from the bottom to the top of the building. The working temperature of the plastic used in the cable is usually maintained at 40-60 ° C. Once a fire occurs, due to the special structure of the cable well, a "chimney effect" will form, and the fire and dense smoke will quickly spread to the upper floors; at the same time, the fire will also follow Spread across the bridge to the connected rooms and walkways. Therefore, cables must be fire-proofed and blocked, and flame retardants are essential.

In addition, the application of flame retardant materials in the field of home appliances is also very important. Statistics from the China Household Electrical Appliances Association show that the current use of plastics in home appliances has accounted for 40% of the weight. It is estimated that many people still remember that Gree recalled more than 2.5 million sets of dehumidifiers sold in the United States two years ago, and received an incident of close to 100 million fines. The cause of this incident was "the dehumidifier did not meet UL flame retardant standards." According to reports, plastic casings for home appliances such as air conditioners, heaters, and kitchen appliances will be required to use non-combustible or flame-retardant materials in the future.

With the advancement of automobile lightweight, more and more lightweight materials are being used to replace traditional metal materials. In particular, the new energy automobile industry has higher requirements on the flame retardancy of materials, especially the charging piles, battery parts, and plastic parts on automotive connectors, all of which require flame retardancy. Take the automotive connector as an example, because the connector contact is metal and has a large number of insertions and withdrawals, the material is required to have good flame retardancy and heat resistance. At present, commonly used materials are PBT, PPS, PA, PPE, PET, etc.

With the improvement of the country's flame retardant requirements for materials and the establishment and improvement of various flame retardant regulations, China's flame retardants will usher in a round of development and development boom, and the entire flame retardant industry will move towards environmental protection, low toxicity, and high efficiency. In the direction of becoming more versatile and multifunctional.


Will halogen-free flame retardants replace halogenated flame retardants in the future?

According to reports, the European Union currently has the most stringent standards for halogen content in materials. For example, the EU's halogen-free standard for IT products is that the halogen content is below 800 ppm. Many Chinese electrical products exported to the EU must meet the requirements of these regulations. Therefore, the new halogen-free flame retardant has become a new product in line with the development trend of international standards, and therefore has become one of the fastest growing varieties of various types of material additives.

"The positioning of my research institute has always been very clear, that is, to be an incubation link between colleges and pure enterprises, to achieve the needs of downstream enterprises from the perspective of practicality." Ye Wen admitted, "halogen-free flame retardants need to be further developed, We must continuously improve its performance and cost advantages. The existing APP flame retardants cannot be avoided, and our research institute has successfully developed an efficient PAPP halogen-free flame retardant system, which is expected to replace APP as the next A core component of the first generation of halogen-free flame retardants. "

The typical advantages of PAPP are: first, it avoids the inherent shortcomings of the APP system, it is not easy to precipitate, and there is no water slip; second, it has higher thermal stability, and the 1% thermal decomposition temperature is 295 ° C, which can adapt to higher processing temperatures Thirdly, the added amount is low. After the compounding, in the pure PP resin system, 20-22% of the added amount can achieve UL94V-0 (1.6mm) flame retardant grade. Fourth, it can be applied to a variety of systems, such as PP. , PE, TPE and PP glass fiber reinforced, filler-filled systems.

At present, the PAPP halogen-free flame retardant system developed by the research institute mainly includes three products: ANTI-610, ANTI-NH2 and ANTI-10. Ye Wen made relevant case introductions for the above three products. For example, PP materials with 30% and 28% ANTI610 added can be used for plastic internals of washing machines and coils of vacuum cleaners, and meet UL94V-0 (1.6mm). The key index of 25% of the amount of ANTINH2 acting on the PP substrate, can be used as the front grill of the heater, and meet the requirements of UL94V-0 (1.6mm), 850 ℃ glow wire, good fluidity, no water skid, At present, domestic customers have used this technology to successfully export products to the Middle East, Europe and the United States and Europe, with an annual export volume of 2 million pieces; 25% of ANTI-10 and EVA can be used in the production of flame-retardant heat-shrinkable tubes, with a fire Self-extinguishing, smooth surface without white spots, no precipitation.

Will halogen-free flame retardants replace halogenated flame retardants in the future? the answer is negative. Ye Wen believes that the selection of flame retardants must take into account many factors, such as compatibility with materials, cost performance, ability to meet fire protection requirements, and stability of flame retardant performance during storage. Different flame retardants are suitable for different flame retardant materials according to their flame retardant mechanism. Blind replacement is not only unnecessary, but there may be new risks.

For example, the use of flame retardants in electronic appliances, construction and other materials is a mandatory requirement of fire safety standards, while halogen-free products may not necessarily meet the requirements of fire safety and processing application conditions, and even in certain application environments, halogen resistance Fuel is the most suitable. For example, in the United States, they use a very large amount of cables containing bromine flame retardants, because bromine flame retardants are best used in practice. In addition, there are some cables that are originally metal armored or ceramicized to achieve the purpose of combusting. At this time, it is not appropriate to be too attached to halogen-free.

"In many cases, the existing flame retardant system is okay, but it may change in the future." Ye Wen, who has been helping modified plastics companies to develop halogen-free flame retardant products at the user side, found that when contacting customers, many The original manufacturers of halogen-resistant flame retardant cables, especially those specializing in small-line products such as computer charging cables and mobile phone cables, are now developing halogen-free flame-retardant products, most of which are phosphorus-based and nitrogen-based resistance.燃 剂。 Fuel.

Ye Wen analyzed in the interview that China has four major motivations for the development of halogen-free flame retardants. In terms of cost, China is a country rich in phosphorus and poor in bromine. The cost and environmental impact of the acquisition, processing, and transportation of bromine are far greater than that of phosphorus. In terms of environmental protection, China's bromine resources are mainly concentrated in Shandong. Since the second half of 2017, Shandong has closed about 600 chemical production companies that switched to production and stopped production for more than 2,000. It is expected that bromine flame retardants will maintain a high level for a long time, which directly promotes the development of halogen-free flame retardant materials. In terms of policies, domestic and foreign flame retardants Environmental protection policies are more favored by halogen-free flame retardants; technically, bromine-based flame retardants have shortcomings in terms of smoke density, smoke toxicity, and drips.

The flame retardant research in the world today is developing towards halogen-free. Some halogen flame retardants will withdraw from the historical stage in the future, and new green environmental protection flame retardants will become a hot spot for future research and development.

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