Halogen free flame retardants are one of the fastest-growing material additives. The purpose of halogen-free flame retardants is to endow non flame retardant materials with flame retardant properties, making them less prone to combustion or self extinguishing under certain conditions. With the continuous development of halogen-free flame retardant technology, there are more and more types of halogen-free flame retardants, and their performance has also been greatly improved. There are two main ways in which halogen-free flame retardants have flame retardant effects: one is to delay fire events, suppress the spread of fire, and inhibit combustion reactions through various mechanisms of action; Another method is to rapidly expand and carbonize the surface of the material to form a protective layer. With the continuous improvement of people's awareness of environmental protection and safety, as well as the continuous research and development of new technologies, halogen-free flame retardants will have greater development in the future. Today, Hefei Wanran will talk about the four major development directions of halogen-free flame retardants in the future, hoping to be helpful to everyone.
Carbon deposition technology.
During polymer combustion, carbon deposition occurs in the condensed phase, which can achieve the purpose of flame retardancy. When the carbon deposition thickness on the surface of the material reaches 1 millimeter, it can withstand a high temperature of 743 ℃ without catching fire. In coatings, pentaerythritol, polyphosphoric acid, and melamine can be used as good carbonization agents, carbonization catalysts, and foaming agents, respectively. Adding them in a certain proportion can prepare high-performance halogen-free flame retardant coatings.
In addition, blending easily carbonized polymers with non carbonized polymers also has good flame retardant effects. For example, blending easily carbonized polyphenylene ether with high impact polystyrene can greatly improve flame retardancy due to carbon deposition; If a small amount of halogen-free flame retardant used for gas-phase fire extinguishing is added, it will have high flame retardant performance, and this carbon deposition technology will be widely used.
Smoke suppression technology.
Due to the fact that halogen-free flame retardants can increase the smoke generation of polymers, smoke suppression has become an important research topic. Smoke suppressant is an additive that can effectively reduce smoke emissions and smoke density. The application of smoke suppressants mainly focuses on polyvinyl chloride, and smoke suppressants containing key compounds are the most effective ones. In addition to the key aluminum oxide and octaaluminate salts, the newly developed smoke suppressant keyate zinc abroad is a smoke suppressant with low poisoning rate and excellent flame retardant performance. Due to the high price of aluminum compounds, zinc borate, aluminum hydroxide, zinc, silicon, and phosphorus are often combined with small amounts of aluminum compounds and added, which is a practical way to solve the current smoke suppression problem.
Microcapsule technology.
Microencapsulation can prevent the migration of halogen-free flame retardants, improve flame retardancy and stability.
Microcapsule technology has become the forefront of flame retardant technology. In recent years, foreign microencapsulated products, such as DuPont's fluorocarbons, have been microencapsulated with polymers for use in polyvinyl chloride, polypropylene, and PVR (polyurethane vinegar), with good results.
Granulation.
Halogen free flame retardants such as aluminum hydroxide, magnesium hydroxide, antimony oxide, etc. New technologies and equipment are needed to micronize them, thereby improving their flowability, processability, and flame retardancy.
