Polymer Synergistic Flame Retardant Technology And Application

In the application of polymer flame retardants, single varieties are rarely used. Most often, several flame retardants or synergistic flame retardants are used together to achieve flame retardancy and reduce the amount of flame retardant or lower costs. Here are some commonly used synergistic flame retardant technologies in recent years.

I. Halogen-Antimony Synergistic Flame Retardant

The compound use of halogen and antimony compounds is the most typical synergistic flame retardant technology and the most widely used flame retardant system.

The synergistic flame retardant mechanism of halogen-antimony system is as follows:

Sb?O?+HX→2SbOX+H?O

5SbOX(s)→Sb?O?X?(s)+SbX?(g)↑

4Sb?O?X?(s)→5Sb?O?X(g)+SbX?(g)↑

3Sb?O?X(g)→Sb?O?(s)+SbX?(g)↑

With the increase of temperature, antimony halide decomposes in the range of 245~565°C to form antimony trihalide, which plays the role of oxygen barrier in its gas phase. In addition, the dehydration of antimony halide and the decomposition of halogen radicals also have the effect of trapping free radicals.

The current research hotspot is to develop antimony substitutes and better synergists in order to further improve the comprehensive performance.

II. Synergistic Flame Retardancy Of Halogens And Inorganic Compounds

In the study of halogen flame retardant flame retardant polyethylene, it was found that dichlorodimethylene bridge loan alkane (DECHL) and tin oxide hydrate has a high synergistic flame retardant effect. For some special flame retardant systems, some metal oxides and halogens synergistic effect is better than antimony oxide.

For example, in the DECHL flame retardant nylon 66 system, iron oxide (Fe?O?), zinc oxide (ZnO) is a good alternative to Sb?O?, especially the addition of iron oxide, to achieve the same level of flame retardancy (0.4m m V-0 level), you can make the addition of DECHL flame retardant to reduce the amount of 40%, showing excellent synergistic effect; and the use of zinc oxide as a substitute for Sb?O?, you can improve the The use of zinc oxide instead of Sb?O? improves the CTI value of flame retardant nylon 66.

In addition, the use of zinc borate in combination with Sb?O? in the DECHL flame retardant nylon 6 system can improve the overall performance of the flame retardant materials, especially the CTI was significantly increased.

III. Halogen-phosphorus Synergistic Flame Retardant

Solid-phase flame retardant phosphorus and gas-phase flame retardant halogen synergize with each other to form a better flame retardant effect from the gas phase to the solid-phase range, phosphorus flame retardant can sometimes also play a flame retardant role in the gas phase.

Halogen and phosphorus flame retardants can produce phosphorus halides and phosphorus oxyhalides at high temperatures, indicating that there is a similar synergistic effect of halogen and antimony between phosphorus and halogens in the gas phase, and thus phosphorus flame retardant can replace some of the polymer materials halogen or antimony to achieve the same flame retardant effect, which reduces a certain cost.

The United States J. Green and other phosphorus, bromine synergistic flame retardant HIPS, ABS and PC and its alloys, etc. conducted a study, and found that excellent synergistic flame retardant effect.

IV. Phosphorus-Nitrogen Synergistic Flame Retardant

The flame retardant mechanism of phosphorus and nitrogen flame retardant system is related to the combination of phosphorus and nitrogen atoms in the molecule.

For the phosphorus and nitrogen atoms are not directly connected to the phosphorus-nitrogen bond flame retardant system, the two may play a separate flame retardant role, may also play a synergistic role.

For phosphorus, nitrogen atoms in the molecule directly connected to the phosphorus - nitrogen bond flame retardant system, the electronegativity of the nitrogen atom Ambassador phosphorus atoms electrophilicity increases, that is, the phosphorus atom on the electron cloud density decreases, Lewis acidic enhancement and is conducive to the occurrence of dehydration carbonization.

The expansion type flame retardant system containing phosphorus and nitrogen elements has the effect of playing the flame retardant effect in the condensed phase and gas phase at the same time.

Phosphorus - nitrogen synergistic flame retardant systems have been widely used in polyolefin resins, engineering plastics, thermoplastic elastomers, rubber materials.

V. Halogen-Silicon Synergistic Flame Retardant

Silicon-containing polymers will form a glassy carbon layer if the silicon remains in the condensed phase during combustion, thus preventing the propagation of heat and matter.

J.R. Ebdon et al. studied the flame retardancy of different chlorosilane-grafted polystyrene and PVOH and found that the flame retardancy of polystyrene containing both silicon and bromine (chlorine) greatly exceeded that of single silicone or bromine (chlorine) flame retarded polystyrene, proving the synergistic flame retardancy of the silicone-halogen system.

The percentage of silicon residue after combustion degradation of polystyrene containing silicon-halogen in a certain range is higher than that of polystyrene containing silicone alone, indicating that the synergistic flame retardant effect of silicon-halogen system occurs in both condensed phase and gas phase.

VI. Polymer Compounding Synergistic Flame Retardant

When polymers burn, the formation of char consumes combustible gases and acts as a heat barrier around the unburned material, thus preventing the further propagation of the flame, and therefore burning char is beneficial to the flame retardancy of the material.

Typical applications, for example, Guennadi E. Zaikov et al. studied the introduction of polyvinyl alcohol into PA66 composites flame retardant, the idea is based on the possibility of increasing high temperature, acid-catalyzed dehydration reaction, that is, through the degradation of PA66 hydrolysis produces acidic products for the reaction to provide the conditions, but also accelerated intermolecular cross-linking into carbon, improving the flame retardant properties.

This char formation system is called “synergistic char formation” because the parameters of char generation and flame suppression are significantly better in polyvinyl alcohol and PA66 blends than in pure polyvinyl alcohol and pure PA66.

VII. Synergistic flame retardancy of initiators

The synergistic flame retardant system of bromine and initiator can be traced back to the bromine flame retardant with diisopropylbenzene oligomer, and HBCD flame retardant polystyrene foam. This compound flame retardant is also an excellent flame retardant for PP,PE,ABS and other materials, characterized by low dosage, good effect, good stability and non-toxicity.

DMDPB and its derivatives are non-peroxide cross-linking modifiers of polymer materials, which can also be used as flame retardant synergists, commonly used bromine flame retardants and DMDPB for compounding.

In addition, bromine-phosphorus-initiator synergistic flame retardancy utilizes the synergistic effect between the flame retardant as well as synergist and co-effector to reduce the amount of bromine flame retardant, thus reducing the impact on the mechanical properties of the material.

Peng Zhihan, Peng Weili, etc. MHP, MHB and initiator and other additives are used to produce a non-surface precipitation flame retardant polypropylene compounds, the flame retardant grade up to UL94 V0, the system has a high flame retardant efficiency, good mobility, non-precipitation and other characteristics.

The system is characterized by high flame retardant efficiency, good fluidity, no precipitation, etc. The bromine-phosphorus-initiator has good flame retardant efficiency, which is of great significance for reducing the amount of bromine flame retardant, and the flame retardant effect is more ideal than the use of a single flame retardant, and the flame retardant system of bromine-phosphorus-nitrogen-initiator can be extended on this basis, and it can be more widely used in flame retardant PP.

Compound synergistic various flame retardant system can get more excellent cost-effective flame retardant products, many polymers rely on a single flame retardant is difficult to get the desired flame retardant effect, so the future of the various types of flame retardant synergistic effect of the research should still be emphasized.

Conclusion

Polymer synergistic flame retardant technology realizes better flame retardant effect and cost-effectiveness through the compounding of multiple flame retardants. Among the many synergistic systems, YINSU Flame Retardant Company's flame retardants also show remarkable synergistic effects. For example, when its T3 is used with bromine flame retardants, it can exert highly efficient flame retardant synergistic effect and significantly enhance the flame retardant performance of materials.

In addition, the synergistic effect of K100 with PE and PVC cable flame retardants is also very obvious, providing a better solution for the flame retardant modification of cable materials. The application of these synergistic flame retardants further expands the scope of application and performance enhancement of polymer flame retardant technology, providing strong support for the development of related industries.

Guangzhou Yinsu Flame Retardant New Material CO., Ltd

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