In recent years, with the increasing awareness of global environmental protection, halogen-free flame retardant materials have been paid more and more attention, especially the high performance halogen-free flame retardant nylon materials are being welcomed by people.
However, unmodified nylon has a poor flame retardant performance, which is a flammable material, and produces dripping in the combustion process, which is very easy to cause fire in the process of use.Therefore, the flame retardant modification of nylon has become a common concern and problem in the academic and industrial circles.Later, scientists added flame retardants to the nylon, changing the flame retardant properties, nylon is more widely used.
For halogen-free flame retardant nylon in the "halogen-free" word, is used to mark the type of flame retardant.Flame retardants are divided into halogenated flame retardants and halogen-free flame retardants. Most of the flame retardants used in the early modification industry are halogenated flame retardants, such as brominated flame retardants.But brominated flame retardants have come under great environmental pressure since the dioxin problem in 1986, and the controversy over brominated flame retardants has not stopped all over the world.
Halogen-free flame retardants solve this problem.Red phosphorus and melamine salts are widely used as halogen-free flame retardants in nylon.Red phosphorus has high flame retardant efficiency and can improve the arc resistance of products, but its storage and color limitations greatly limit its application in nylon, generally only used in nylon 6.Another halogen free flame retardant used in nylon is melamine salt, mainly melamine urate and phosphate.They have good flame retardant efficiency, but poor thermal stability and poor electrical performance in humid environment due to easy moisture absorption.
Halogen free and flame retardant nylon is added flame retardant containing very little or no halogen elements bromine and chlorine.Halogen-free flame retardant nylon products have excellent flame retardant performance, flame retardant grade UL94V0, with low precipitation, anti dripping, high electrical performance and heat resistance, high CTI value, good electrical performance, high impact strength, friendly to the environment, environmental protection.Suitable for making electrical connector.Brominated flame retardants or halogen-free flame retardants conforming to European ROHS standards were added to the materials to improve the flame retardancy performance of the composites.The granular nylon can withstand processing temperature of 260℃.
In the process of using halogen-free flame retardant nylon particle materials, we sometimes encounter some labels, such as ul94v-0, ul94v-2, etc.
Flammability UL94 is the most widely used standard for the flammability of plastics.UL94V0 class can meet five standards and requirements: one is that no samples are burned for more than 10 seconds after the test flame is removed;Second, for each set of 5 samples, after 10 times of ignition, the total combustion time with flame is no more than 50 seconds;Third, no samples have been burned to the fixture;Fourth, without any sample, the melted liquid drops of combustion ignited the cotton at the following 12";Fifth, there are no samples. After the second removal of the test flame, the continuous redness burns for more than 30 seconds.Such a standard, can completely avoid the occurrence of fire.
With the extensive application of nylon engineering plastics, more and more varieties of flame retardants, and the deepening development and research of flame retardation technology, the development direction of flame retardant nylon will be the following four directions in the coming decades:
One is the compounding technology of flame retardants.Many flame retardants manufacturers in the world are engaged in the development of new collaborative system, that is, multiple flame retardants compound, in order to reduce the amount of flame retardants, improve the flame retardant performance, not only reduce the cost of flame retardant materials, but also reduce the loss of physical properties.
The second is halogen-free, low toxicity and low halogenation.Many countries have banned or restricted the use of halogen flame retardants, instead of phosphorus, nitrogen and inorganic flame retardants.
Third, multifunctional.In some industries, nylon is required to have flame retardant performance, but also required to have such as thermal conductivity, electrical conductivity, antistatic, etc., need to add a large number of other additives to meet the requirements of users.
Fourth, cost and performance balance.Develop efficient flame retardant system to reduce the influence of flame retardants on the physical properties of materials, and reduce pollution and cost.