Why is black PP material more difficult to achieve halogen-free and high flame retardant than light-colored PP material?

However, with the expansion of demand for PP in the automotive industry, construction industry, electrical insulation materials industry and shipbuilding industry, people have put forward higher requirements for the flame retardant performance of PP.

Polystone chemical halogen-free flame retardant PP particles

However, the limiting oxygen index value (LOI) of PP is only 17.0%-18.5%, which is a flammable material, and the burning rate is low when burning, the calorific value of combustion is large, and it is easy to produce droplets when burning, which is easy to cause flame propagation. The secondary fire has limited the use of PP in many fields, so it is especially important to expand the application field by modifying the flame retardant of PP. The flame retardant currently applied to PP can be classified into a halogen-based flame retardant, a metal hydroxide, a silicon-based flame retardant, a nano-flame retardant, a phosphorus-based flame retardant, an intumescent flame retardant, and the like. Among them, intumescent flame retardant (IFR) is a low-toxic halogen-free flame retardant with P and N as main components, which is in line with the development trend of environmental protection of flame retardants, and is a kind of environmentally friendly flame retardant with broad application prospects. IFR mainly acts as a flame retardant by thermal decomposition to form a foamed carbon layer through the interaction between the acid source, the carbon source and the gas source.

IFR has the advantages of less added amount, high efficiency, low toxicity, low smoke and no droplets. It has better flame retardant performance than other flame retardant materials. Therefore, intumescent flame retardants are receiving more and more attention. Applied to various polymer matrix materials, it has become the most active research object in the field of flame retardant research.

The most used acid source in IFR is ammonium polyphosphate (APP), silicate, maleic anhydride, ammonium phosphate, triphenyl phosphate, melamine phosphate, urea phosphate, boric acid or borate; The basis for forming the expanded carbon layer is dehydrated and charred during the combustion process. The carbon source mainly includes PER, phenolic resin, thermoplastic polyurethane (TPU), polyamide, butyltetramethylene, cyclohexanol, starch, maltose, triazine compounds, etc.; when the gas source is heated, it can be decomposed to produce a large amount of non-toxic, A non-flammable gas that dilutes the oxygen in the air or the flammable gas on the surface of the substrate to provide a flame retardant effect. Commonly used gas sources are mainly melamine (MEL), dicyandiamide, APP, urea and the like. The flame retardant application of intumescent flame retardants on polypropylene light-colored parts is now quite mature, but the flame retardancy on high-blackness polypropylene parts still has some difficulty. But there are also manufacturers who do quite well in this area, such as Guangdong Juishi Chemical.

First, the advantages of high black PP compared to light PP?

In the PP product molding process, in order to dye the product, improve the anti-aging performance and UV resistance, a certain amount of black masterbatch is generally added, and the PP product added with the black masterbatch has a longer service life than the light-colored PP product. This is especially important for PP products that are often exposed to outdoor PP, such as water, drip irrigation, and communication cables.

Second, black PP material flame retardant?

Brominated ruthenium flame retardants mainly rely on gas phase and condensed phase to exert flame retardant effect. Toner and filler have little effect on flame retardancy, but they are environmentally restricted. The flame retardant mechanism of halogen-free phosphorus-nitrogen is to expand into charcoal, and to isolate oxygen and heat source to play a role in flame retardant.

The main component of the black masterbatch is carbon black. The carbon black itself is flammable, has a large specific surface area, and has many micropores on the surface. It is easy to form a space network channel and is not easily damaged. The presence of these micropores will affect the density of the flame retardant carbon layer. Sex, so that the carbon layer does not have a good insulation.

In the case of the same amount of charcoal, the flame retardant does not reach the effect, and finally the flame retardancy of the black component is worse than that of the light-colored component, and the addition amount of the black powder or the black mother is larger, and the flame retardant is more Difficult to achieve, and blindly increase the amount of flame retardant, will deteriorate the performance of the material, the material loses good processability and usability, and also has great challenges to the cost of composite materials.