Coating compound production line
DATE：2021/5/13 8:38:29 / READ： / SOURCE：This station
Coating compound production line
Inorganic flame retardant is a kind of halogen-free flame retardant, which has the advantages of high safety, smoke suppression, non-toxic and low price. Al (OH) 2 and Mg (OH) 2 play an important role in the production of hot phosphite and miniaturization. They have the advantages of Al (OH) 2, hydrogen oxidation, low smoke emission and no secondary pollution. However, the addition of good stability, non-toxic, non-volatile, non corrosive gas, and the addition of Ouli can greatly reduce the mechanical properties of the material, and the amount is large, which is about several times of that of halogen flame retardant. A large number of inorganic flame retardants with certain acidity or alkalinity, hydrophilic groups on the surface, coating composite production line www.handern.comThere are still drops in other combustion. In addition, most inorganic flame retardants have polarity and are easy to absorb water. However, PE is a nonpolar molecule and lacks polar groups on the macromolecular chain, so it has poor compatibility with inorganic flame retardants, and it is difficult to form a good bond and firm adhesion at the interface of the filling system. Therefore, it is necessary to modify the matrix of flame retardants and resins. Generally, silane coupling agent, titanate coupling agent, flame retardant, fatty acid salt and other additives can improve the physical and mechanical properties of flame retardant materials. The function of coupling agent is to increase the compatibility of inorganic flame retardant and polymer, and the addition of fatty acid salt is to prevent condensation during use. The dispersion, mechanical properties and fluidity of the LLDPE / Mg (OH) 2 composites filled with surface treated Mg (OH) 2 were better than those of the untreated LLDPE / Mg (OH) 2 composites, which improved the mechanical properties of the materials and had little effect on the flame retardancy. When the coupling agent is not used for surface treatment, the introduction of magnesium hydroxide can greatly reduce the impact strength, tensile strength and elongation at break of the material, which indicates that the adhesion between magnesium hydroxide and LDPE is not good and there are a lot of defects.
The amount of coupling agent is the best, Mg(OH)2 The surface of particles can not be completely coated by coupling agent, The results showed that the effect of modification was poor; If the amount of coupling agent is too much, the adhesive force between the inorganic filler and the resin will be reduced, resulting in the decrease of the properties of the composite and the increase of the cost of the material. Therefore, the appropriate dosage should be found according to the requirements in practical application. The particle shape (particle size and particle size distribution) of inorganic flame retardant is an important factor affecting the properties of flame retardant materials. The smaller the particle is, the larger the specific surface area is, and the larger the interface is. For particle size distribution, the narrower the distribution, the better. The wider the particle size distribution is, the greater the difference of particle size is, and the worse the mechanical properties are. The particle size of Mg (OH) 2 can reach 5 ~ 6pm after mechanical crushing, but there are also particles of 20pum or more. Compared with ordinary Mg (OH) 2, nano Mg (OH) 2 can improve the oxygen index of LDPE better and reduce the amount of Mg (OH) 2, which is helpful to prevent the decrease of processability and mechanical properties caused by excessive addition. The reason may be that the size of nanoparticles is small, the specific surface area is large, the contact surface with the polymer is large, and there are more chemical active points on the surface, which is more conducive to the combination with the polymer than micron in both physical and chemical aspects. In addition, nano Mg (OH) 2 is prepared by chemical method, and its purity is higher than that of natural Mg (OH) 2, which is also the reason for its high flame retardancy. Coating compound production line www.handern.com
Boric acid flame retardant is a kind of multifunctional flame retardant, It mainly includes zinc borate, iron borate, barium metaborate, etc. in its expansion, zinc borate (chemical composition: 2zno.3b2o3 ● 5H2O) has the largest output and consumption, and is most widely used. It forms a glassy coating under the action of flame, and then at high temperature (290 ° C) Dehydration, play the role of endothermic cooling.
At the same time, it can promote carbonization and smoke suppression, so as to play the role of flame retardant. Zinc borate is often used as flame retardant synergist in combination with other flame retardants. Coating compound production line www.handern.com
At present, phosphorus compounds are one of the most important flame retardants. Phosphorus containing inorganic flame retardants have been widely used because of their good thermal stability, nonvolatile, non corrosive gas, long-lasting effect and low toxicity. Red phosphorus as flame retardant and traditional flame retardant (such as halide / sbo2) It can be used alone or together with other flame retardants. It has the advantages of low dosage, easy moisture absorption, easy oxidation, good flame retardant effect with trees, high performance, refinement and functionalization of general plastics, explosion of dry red phosphorus dust, poor fat compatibility and good durability. But red phosphorus will be released when it contacts with the air for a long time, which can not be directly used in PE, because it is highly toxic phosphine gas, which is a way to pollute the environment. Coating compound production line www.handern.com
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