Commonly Used Environmental Friendly Flame Retardants In Heat Shrinkable Materials

- Nov 14, 2018-

Eco-friendly flame retardants commonly used in thermal shrinkage materials

In the production process of heat-shrinkable sleeve and other heat-shrinkable materials, flame retardants are often added to meet the requirements of product flame retardant. However, with the increasing awareness of global safety and environmental protection, people have higher and higher requirements for fire safety and product flame retardant. Halogen-free, low smoke, low toxicity environment-friendly flame retardants have become the pursuit of people. The goal. Then, what are the commonly used environmental friendly flame retardants in heat shrinkable materials?

At present, nearly 80% of the flame retardants used in plastic modification in China are halogen-containing flame retardants. Polybrominated diphenyl ethers and polybrominated biphenyls are the representatives. The brominated flame retardants have high efficiency, low dosage, little influence on the properties of materials and moderate price. Compared with other types of flame retardants, their efficiency/price ratio is more superior. 70%-80% of the electronic and electrical products for export in our country use this kind of flame retardant. However, the bromine-antimony flame retardant system produces a lot of smoke and corrosive gases during pyrolysis and combustion. In recent years, some European Union countries believe that the combustion of bromine flame retardants will produce toxic and carcinogenic PBDD and PBDF. In February 2003, the European Union issued two bans, RoHS and WEEE. RoHs (The Restriction of Hazrd OusSubstances Directive),It stipulates that all electronic and electrical equipment sold in European Union countries shall not contain PBBs and PBDEs as of January 1, 2006.

Common environmental friendly flame retardants in heat shrinkable materials:

Environmental friendly brominated flame retardants

1, ten bromo two phenyl ethane 8010

8010 is not a polybrominated diphenyl ether, and it is absolutely impossible to produce PBDD or PBDF in combustion; the relative molecular weight of 8010 is 971; the content of bromine is 82%, which is equivalent to the content of bromine in DBDPO (83%), so its flame retardancy is basically the same; the initial melting point is 345 and its thermal stability is higher than that of DBDPO (305); its light resistance and non-permeability are better than DBDPO, and most acceptable. Expensive is that its flame retardant plastic can be recycled, which is not the characteristics of many brominated flame retardants. 8010 industrial products are white crystalline powder with average particle size of 3 micron, free flow and micro-granularity. It is easy to disperse in plastic modification and the color of plastic products is free. Moreover, the cost of industrialization is equivalent to that of DBDPO, which is the most ideal substitute for DBDPO. As an additive brominated flame retardant, 8010 also needs to be used with antimony compounds in the use process, and the proportion of antimony compounds is the same as that of DBDPO/antimony compounds. Compared with DBDPO, 8010 is more suitable for engineering plastics with high temperature and high viscosity characteristics.

2. Brominated epoxy resin

Brominated epoxy resin used as flame retardant is also called tetrabromobisphenol A epoxy resin oligomer. Its bromine content can reach 50%, and its molecular weight is between 1000 and 45000. It can be divided into EP and EC types. Compared with EP and EC types, the former has better light resistance, but lower bromine content, while the latter has better impact strength. Commercial brominated epoxy resin is a mixture of opalescent semi-transparent wafer and white powder. Domestic brominated epoxy resin has irritating odor, while Israeli Dead Sea bromide products have no odor. Brominated epoxy resin has satisfactory melt flow rate, high flame retardant efficiency, excellent thermal stability and light stability, and can give flame retardant substrates good mechanical properties, products do not frost. Low phase molecular weight brominated epoxy resin is suitable for flame retardant ABS and HIPS, and high phase molecular weight is suitable for flame retardant ABS/PC alloy and engineering plastics such as PC, PET, PBT. It needs to be used in combination with antimony.

3, brominated polystyrene

The development of brominated polystyrene is similar to that of brominated epoxy resin, and it is also a fast developing flame retardant in recent years. Brominated polystyrene is white or light yellow powder or granule, bromine content is about 60%. The thermal decomposition temperature is higher than 310 C. It has the advantages of high molecular weight, good thermal stability, good dispersion and compatibility in polymers, easy processing and no frost. Brominated polystyrene is named brominated polystyrene and polybrominated styrene according to their synthetic routes. It can be seen from the nomenclature that brominated polystyrene is accomplished by brominating polystyrene. Polybrominated styrene is protected by vinyl bond first, then brominated, and then restored by vinyl bond. The brominated styrene was polymerized again. Whether solvent is used in the synthesis process can be divided into solvent method and non solvent method. As solvent consumption is low, it is usually synthesized by solvent method.

Two. Phosphorus flame retardants

1. Red phosphorus Masterbatch

Among the non-halogen flame retardants, red phosphorus is a better flame retardant, which has the advantages of less addition and wide use. Ordinary red phosphorus is easy to absorb moisture and has poor compatibility with macromolecule materials. It is especially easy to cause spontaneous combustion and can not be used in practice. Microencapsulated red phosphorus flame retardant reduces the activity of red phosphorus and solves the compatibility. The content of red phosphorus is about 85%, but the problem of spontaneous combustion has not been effectively solved, and the dust pollution is serious.

Red phosphorus masterbatch is a dark red particle, which is composed of red phosphorus and inorganic flame retardants such as aluminium hydroxide and expansive graphite. The safety problem has been solved. It has low smoke, high flame retardant efficiency, no dust pollution, excellent processing performance, low density, good thermal stability, less decline in physical properties of products, no frost, no migration, no corrosion in the process of processing. In particular, the product has a high resistance to leakage trace index (CTI), which has obvious advantages in the application of electronic and electrical appliances.

The main disadvantage of red phosphorus masterbatch is the tone problem. Besides dark red and black, it can not give products more color choices.

Red phosphorus masterbatch is used for flame retardant of general plastics, rubber, polyethylene, polypropylene and other oxygen-deficient materials.



    目前国内塑料改性用阻燃剂近80%为含卤阻燃剂,其中以多溴二苯醚和多溴联苯类物质为代表,溴系阻燃剂效率高、用量少,对材料的性能影响小,且价格适中。和其它类型的阻燃剂相比,其效能/价格比更具有优越性,我国供出口电子电气类产品中70%~80%都用此类阻燃剂。但溴-锑阻燃体系在热裂解及燃烧时会生成大量的烟尘及腐蚀性气体,而且近年欧盟一些国家认为溴系阻燃剂燃烧时会产生有毒致癌的多溴代苯并恶瑛(PBDD)和多溴代二苯并呋喃(PBDF),2003年2月,欧盟出台了RoHS和WEEE两个禁令,其中RoHs是限制有害物质的禁令(The Restriction of Hazrd OusSubstances Directive),它规定自2006年1月1日起,在欧盟国家销售的所有电子电气设备,不能含有多溴联苯及多溴二苯醚。