Development trends and simple classification of flame retardants

Flame retardantWith the development of the synthetic materials industry, a large number of synthetic resins are used In the fields of construction, transportation, electrical appliances, aviation, daily necessities and other fields, because organic resin compounds are flammable, people have gradually put forward more and more urgent requirements for the flame retardancy of materials. The purpose of using flame retardants is to make flammable materials become flame-retardant materials, that is, they burn very slowly when in contact with a fire source, and they can quickly stop burning and extinguish when they leave the fire source. It should be said that in terms of reducing the flammability of polymers, one can also consider synthesizing heat-resistant materials with high cooked oxygen stability, but such polymer materials are often very costly and difficult to meet other requirements. Therefore, the method of adding flame retardants is more practical and economically feasible. There are two classification methods of flame retardants.

Categories by composition are as follows:

Added flame retardant Mainly include phosphate esters, halogenated lamps and oxidation agents, etc., which are simply blended with polymers and do not react chemically. Reactive flame retardants are used in the preparation of polymers. As one of the raw materials, it becomes part of the polymer molecule through chemical reaction, so it has little impact on the performance of the plastic and has long-lasting flame retardancy. It mainly includes halogenated acid anhydrides and phosphorus-containing polyols.

The basic requirements for flame retardants are as follows:

(1) Flame retardants do not reduce the physical and mechanical properties of the polymer, that is, after the plastic is flame-retardant, its original physical and mechanical properties are not damaged. In particular, it does not reduce the deformation temperature, mechanical strength and electrical properties;

(2) The decomposition temperature of the flame retardant must be consistent with the polymer The thermal decomposition temperature is adapted to the flame retardant effect, and the halogen-free flame retardant cannot decompose during plastic processing and molding, so as to avoid the gas generated by decomposition, polluting the operating environment and discoloring the finished product;

(3) It is durable and its flame retardant effect cannot disappear during the use of the material;

(4) Weather-resistant;

(5) Low price. With the increasing popularity of flame retardants, The amount of additives in products tends to increase, so low price is very important.

Since the 1970s, with the development of plastics They are widely used in various sectors and many countries have increasingly strict requirements on the flammability of plastic materials. Therefore, flame retardants are developing rapidly and are the fastest growing type of plastic additives. At present, the production and consumption of flame retardants has reached a considerable scale, and research work is also very active. The United States is a major country in the production and consumption of flame retardants. Its consumption is second only to plasticizers and ranks second among monolithic additives. Currently, the main consumers of flame retardants are polyoxyethylene, polyoxyformate, unsaturated polyester and polystyrene. Flame-retardant plastics account for the largest proportion, and the fastest growing is polyurethane foam plastic.