Effect of Flame Retardant System on Properties of Nylon
Some liquid flame retardants increase the fluidity of the melt. The flame retardant belongs to a small molecular substance, and its addition can play a plasticizing role in the nylon resin matrix to improve the fluidity. The typical flame retardant MCA is both a flame retardant and a good lubricant. The addition of a flame retardant may result in a decrease in mechanical properties such as impact strength and flexural strength of the nylon. However, with the increasing requirements for various engineering plastics, the nylon is reinforced and modified while satisfying the flame retardant properties of the products. Currently, the use of glass fibers to strengthen nylon is a widely used method, glass fiber reinforced. Nylon products have high strength, high heat distortion temperature, low molding shrinkage, decreased fluidity, and greatly improved impact strength. The development trend of flame retardants for nylon is currently available for nylon flame retardants. Brominated flame retardants such as decabromodiphenyl ether, decabromodiphenylethane, etc., phosphorus flame retardants such as red phosphorus, melamine , cyanurate (MCA), solid flame retardants such as antimony trioxide, zinc borate, etc., the synergistic effect between some flame retardants.
In terms of the effect and amount of use, the halogen-containing flame retardant system is the most widely used in the nylon flame retardant system. Polyhalogenated styrene is widely used in halogen-containing flame retardant systems. It is a homopolymer of dibromostyrene, has excellent thermal stability and good miscibility with nylon, and is processed during processing. It has good fluidity, but its light stability is poor and its cost is high. It is not widely used in China. It is widely used in China for decabromodiphenyl ether because of its high bromine content, low added amount and flame retardant effect. Good and low cost, and become the most economical type of flame retardant preferred by many domestic enterprises, but it emits harmful gases and toxic substances DPO (so-called dioxins), which are extremely harmful to the human body. Harmful. In recent years, due to the promulgation of the EU RoHS/WEEE directive, experts and scholars in the industry are working hard to find practical and efficient environmentally friendly halogen-free flame retardants.
Halogen-free flame retardant systems are widely used in red phosphorus and melamine salts. However, red phosphorus can only be used for black products because of its own color, and it is generally only used in nylon 6, the application range is extremely narrow; in addition, the most common application is melamine salts, mainly melamine urea and phosphate. However, its flame retardant effect is not good, the addition amount is large and can not reach a high flame retardant grade, and can only be applied to occasions where the flame retarding requirement is not high. Based on this, in recent years, a new environmentally friendly flame retardant, decabromodiphenylethane, has been developed, which has the same high bromine content and better flame retardant efficiency as decabromodiphenyl ether, but it has good It has the advantages of thermal stability and light stability, and is not easy to bloom. It can be used in place of decabromodiphenyl ether in nylon.
Development status of flame retardant nylon So far, most of the flame retardant products related to PA are based on halogen-containing compounds, and the smoke, toxicity and corrosive gases generated during flame retardant bring to the production, application and environment. Sub-disasters and international debates on dioxin issues have made such flame retardants, although currently playing a pivotal role in the flame-retardant arena, people have been and are working hard to find alternatives to such flame retardants, namely Halogen free flame retardant. Although red phosphorus is one of them, its application in light-colored products is limited due to its color problem, and it can release toxic phosphine. On the contrary, the halogen-free intumescent flame retardant not only can give a better overall balance in the performance of the flame retardant material, but also has wide applicability in color, so the halogen-free expansion flame retardant technology has gradually been paid attention to. .
Regarding the halogen-free expanded flame retardant white nylon 66, China is still in the basic research stage, and the international market white flame retardant nylon has just entered the production stage. Since the 1980s, the A3X series of products with red phosphorus as a flame retardant has been introduced. KR4455, introduced in 1995, is a flame retardant nylon 66 product with inorganic hydroxide as a flame retardant. It improves the interface properties of inorganic fillers and matrix resins, and compensates for the effects of such flame retardants on the mechanical properties of materials.
In terms of other flame retardant varieties, BASF also introduced KR4205, a melamine compound that is a flame retardant system. The company's flame retardant products with red phosphorus as a flame retardant will contain color. Some products are required to be made in true color, so red phosphorus may sometimes be limited. Lati Company of the United States has created a flame-retardant nylon copolymer of Latalnid68 HZVOH, which is suitable for the production of electrical and electronic film products. Its processability and resistance to fire are very good, so it can be used for connectors and miniatures. Production applications such as sockets. Foreign countries have also studied the composite materials of flame retardant nylon 66. Recently, the United States Alliance Signal Company introduced a flame-retardant nylon packaging material, called Staticule MPP, which can control the development of static electricity. Through metallization products, the company's curing process achieves flame retardancy and eliminates static charge. A new type of film for use in roll rolls, belts, shields and drapes.
In addition, in terms of composites, Rhodia has developed a variety of flame retardant nylon composites, mainly organic phosphide as a flame retardant, products such as ehnyl C52G3MZ25. Edward DW et al. studied the application of iron compounds in halogen-free flame retardant nylons. They mainly use inorganic iron compounds, polyphenylene ethers, and zinc borate to increase the content of carbon compounds. The effect of burning. PieteGijsman et al. studied the difference in flame retardant mechanism between melamine-cyanurate in PA6 and PA. They believed that the main degradation product of PA6 is caprolactam, and the main degradation product of PA66 is cyclopentanone. The effect in PA66 is better than in PA6. http://news.chinawj.com.cn
Editor: (Hardware Business Network Information Center) http://news.chinawj.com.cn
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