Have you gotten these commonly used flame retardants for plastics？-Melamine cyanurate
With the increasing application of engineering plastics in the fields of electrical appliances, automobiles, and communication equipment parts, many countries and organizations around the world have introduced test standards for the flame retardant properties of plastics to prevent fires from burning plastics. Test standards for flame retardancy Therefore, research on plastic flame retardants is gradually increasing.
Flame retardants are additives that can improve the flame retardancy, self-extinguishing and smoke suppression properties of materials. It can prevent the material from being ignited and inhibit the spread of flame. Flame retardants are mainly used in various polymer materials (rubber, plastic, fiber, etc.). Today, the rapid development of engineering plastics indirectly drives the research and sales of flame retardants.
Flame retardants can be divided into halogen flame retardants, phosphorus flame retardants, nitrogen flame retardants, silicon flame retardants, boron flame retardants, metal hydroxide flame retardants, and intumescent flame retardants according to their ingredients. Burning agent, etc. Melamine cyanurate
1. Halogen flame retardant
Halogen flame retardants are flame retardants containing halogens. Halogens refer to elements of group VIIA, including fluorine (F), chlorine (Cl), bromine (Br), and iodine (I), and their flame retardancy increases sequentially. However, only chlorinated flame retardants and brominated flame retardants are widely used in industry.
Halogen-based flame retardants are currently one of the most used flame retardants in the world. The biggest advantage of halogen-based flame retardants (especially brominated flame retardants) is that they have high flame-retardant efficiency and moderate cost, but their disadvantage is that they will produce toxic hydrogen halide gas when burned.
Halogen flame retardants There are currently dozens of halogen flame retardants, which can be applied to most engineering plastics.
2. Phosphorus flame retardant
Phosphorus flame retardants are highly safe and will not generate toxic gases when burned. It is one of the most widely used and practical flame retardants. Phosphorus flame retardants have particularly good flame retardant effects on oxygen-containing polymers, so they are mainly used for flame retardant materials such as epoxy resin, polyurethane and polyester. For oxygen-free hydrocarbon polymers (such as PE, PP, PS, etc.), the effect of using phosphorus flame retardants alone is not good, and can be used in conjunction with magnesium hydroxide and aluminum hydroxide. Phosphorus flame retardants are mainly divided into three categories:
a. Inorganic phosphorus flame retardant
This category mainly includes red phosphorus and various phosphates. This is the longest-developed category. It has the advantages of good thermal stability, non-volatility, low toxicity, and no toxic gases. The disadvantage is that the water resistance is poor, which affects the mechanical properties of the material, and the red phosphorus itself is dark red, so the finished product can only be made into red or black.
b. Organic phosphorus flame retardant
Including organic phosphate, phosphate, and phosphite. Most of the organophosphorus flame retardants are oily and are not easily mixed with particulate resins, so they are often used in thermosetting unsaturated polyester, polyurethane, PVC paste resins, etc.
c. Halogen-containing phosphorus flame retardant
This type of flame retardant combines the advantages of halogen flame retardants and phosphorus flame retardants, and has a synergistic effect with other flame retardants, and can be mixed and used to increase flame retardancy.
3. Nitrogen oxides
Nitrogen flame retardants are also known as triazine flame retardants, mainly melamine and its derivatives.
This kind of flame retardant has low volatility, halogen-free, low toxicity, low smoke, no corrosive gas, stable to heat and ultraviolet, high flame retardant efficiency and low price, and can be applied to epoxy resin, PVC, PA, PP , PU, ??PET, PS, ABS and other plastics. The disadvantage is that it will reduce the processing performance of the plastic.
On the whole, nitrogen-based flame retardants do not perform well when used alone, and can be mixed with other flame retardants.
4. Metal hydroxide
There are mainly two types of aluminum hydroxide and magnesium hydroxide (aluminum hydroxide has better performance and higher usage), which has the functions of flame retardant, smoke suppression and filling. However, the effect of this kind of flame retardant is general, usually more than 50% is needed to show a better flame retardant effect. It can be used for flame retardant of unsaturated polyester, PP, PE, PVC, EP and phenolic resin.
5. Boron flame retardant
Mainly include ammonium borate, barium borate, zinc borate, borax and so on. The largest amount is zinc borate
Zinc borate flame retardant has the advantages of smoke suppression, non-toxicity and low price. It can be used in PVC, EP, unsaturated polyester, PBT, PET and PA. It can be used alone or in combination with other flame retardants. The refractive index of zinc borate is similar to that of plastic. It has little effect on the transparency of the product, does not affect the electrical insulation of the product, and can also improve the arc resistance. It is a transparent flame retardant.
6. Intumescent flame retardant
It is a flame retardant that has received widespread attention in recent years and is divided into physical expansion type and chemical expansion type. It has the advantages of halogen-free, low smoke and low toxicity. Its flame retardant principle is that the flame retardant is heated and expands to block the heat and oxygen between the fire source and the polymer to prevent further decomposition or burning of the material.
Compared with other varieties, intumescent flame retardants have the advantages of environmental protection, high efficiency and low price, and have great potential for development.