What are the reasons for the different effects of flame retardants?

The common problem of many manufacturers is that the flame retardant effect of the flame retardant is not obvious, and the flame retardancy is uneven. On the same board, some places have obvious flame retardancy, some places have poor flame retardancy effects, and some places are flame retardant. The effect is poor, the flame retardant effect is poor in some places, and the flame retardant performance is quite different in some places.

The reasons for the different effects of flame retardants are as follows

1. Human factors, the amount of flame retardant added to the extruded board is small, generally less than 10%, so that the flame retardant is evenly distributed into the material, stirring is the most important part, in order to make every 100 grams of material evenly contain 5 Gram of flame retardant requires a lot of manual stirring and professional mixer mixing. Many manufacturers directly sprinkle the flame retardant on the surface of the material and send it directly to the feeder. Although the feeder stirs by itself, it only takes a short time. It can form a small area of ​​dispersion and be squeezed out, on the outer wall of Fangshan.

2. Equipment factors, different equipment manufacturers promote the screw nut clearance, speed, plasticized dispersing nut design technology is different, the plasticization, dispersion, and residence time of the material inside the nut are also different. The usual flame retardant is mainly hexabromocyclododecane. We usually use the melt temperature as the standard for the flame retardant board. It is not the heating temperature, but the shearing of the material by the screw to generate a large amount of shear heat. It is transferred to the material and is extruded, so the more the shear heat of the material is accumulated by the equipment, the higher the heating temperature and cooling water in long-term production.

3. Flame retardant factors. Domestically produced flame retardants are mainly powder and particles. The density of powder flame retardants is different from the material particles. During the stirring process, the friction static electricity can only absorb a small part, and most of them settle along the particle gap in the stirring. At the bottom of the equipment, the flame retardant is unevenly dispersed. The powder adsorbed on the particle surface first comes into contact with the screw nut. When it encounters high temperature, it decomposes seriously. During the decomposition process, the free bromine reacts with the screw nut to produce iron bromide and peels off, which is very corrosive to the equipment and is not recommended for use. The particles are covered by the flame retardant manufacturer with resin composite powder. The density and volume are close to plastic particles. It is easy to evenly disperse into the material during the mixing process.

The total contact area with the screw nut during the extrusion process is small, and the decomposition is also less. being widely used. However, the processing conditions of particle materials are relatively strict. Advanced plastic modification equipment needs to cover the ultra-high content of composite flame-retardant ingredients in a small amount of carrier resin at low temperature. Most of the domestic flame-retardant particles are simple singles. For twin-screw processing, the content of flame-retardant components cannot exceed 65%. The screw advances quickly and requires high processing temperatures to decompose part of the flame-retardant components.