Several Key Points That Determine The Quality of Black Masterbatch

1. High dispersion

Black masterbatch is produced using carbon black. Raw carbon black is a very difficult and dirty mixture, it is dusty, light and fluffy. Unless large-scale treatment measures are taken, it will dirty machines and workers and make the working environment dirty.

Because of this, casters generally choose to use a resin carrier, that is, black masterbatch, to complete the pre-dispersion of carbon black. This resin carrier is clean, free flowing and easy to use. In addition, apart from being dirty, carbon black also has the characteristic that it is difficult to disperse.

If the raw carbon black is melted directly during injection molding, the coloring effect will be very poor. Undispersed carbon black streaks and spots will be obvious next to less colored areas. Standard injection molding machines cannot effectively disperse raw carbon black.

This difficult dispersion of carbon black also troubles color masterbatch manufacturers. High-load black masterbatch produced by single or double screw extruders has very poor dispersion. When the end user mixes or molds these black masterbatches, its performance is only slightly better than carbon black, but the effect is equally unsatisfactory.

To achieve a stable high dispersion, a high level shear mixer must be used to mix carbon black, such as a mixture of FCM or BANBURY. With sufficient intensity, these mixers can completely mix the carbon black and base resin together. The type of carbon black used also affects the dispersion. The smaller the carbon black particles, the more difficult it is to disperse.

The application of thin wax is the most demanding in terms of dispersion. The final product of masterbatch with poor dispersion can be easily seen by the naked eye from the corners. In addition to the lack of aesthetics, the poor dispersion of carbon black in the film significantly reduces the anti-weathering performance of the black film.

Small particles with good dispersion are the main feature of the fiber industry. These fibers are used in ropes, yarns, carpets and other industries. Large machines produce 30,000 strands of fine fibers at a speed of more than 5,000 meters per minute. If the dispersion of the masterbatch is too poor, it will break the fiber and cause production to stop.

 

2. Strong coverage

The second factor that determines the quality of black masterbatch is covering power, which is especially important for masterbatch used for waste or recycled polymers. In these cases, the role of black is to cover other colors in the waste. Large particle carbon black has poor coloring ability and is not easy to cover all other underlying colors. As a result, the final product only gets a deviated color. In the melting process, the ability to correctly select carbon black with high coloring power to cover the existing color is the so-called covering power.

 

3. Good liquidity

The third factor that determines the quality of black masterbatch is rheology and fluidity. If a masterbatch itself has good dispersion, but it cannot flow into the material to be molded, the production effect will not be ideal.

Generally speaking, the base resin used to produce masterbatch has higher rheology. In order to save costs, some masterbatch manufacturers use reused materials, waste or recycled materials as resin carriers. The flow properties of the masterbatch produced in this way will be significantly reduced. If the rheology is not good, the mold will encounter trouble in cycle time and appearance treatment.

It is worth noting that if the dispersion and rheology are not high, some end users will compensate by increasing the dilution ratio, but this practice will only increase the cost of masterbatch. Masterbatch with the minimum dilution ratio can produce a uniform, well-dispersed black.

 

4. Compatibility should be large

Compatibility is the fourth factor that determines the quality of black masterbatch. If the masterbatch is produced from off-cuts or recycled materials, it may contain contaminants or other infusible polymers. This will cause some unexpected and difficult to control troubles, wasting the time and raw materials of the end consumer. At this time, a primer resin can be selected to produce high-quality masterbatch, which has good compatibility during the melting process.

High-quality masterbatches can be produced using LLDPE, LDPE, HDPE, PP, PS, SAN, PA and other materials. Special polymer masterbatches are available if engineering grade and strict physical properties are specified. Several large international masterbatch manufacturers are conducting research to produce so-called "global universal" masterbatches. These masterbatches can be widely compatible with other raw materials, have good rheological properties, and can be flexibly applied.

NANJING HAISI is professional manufacturer of Black Masterbatch extruder, we supply Twin Screw Extruder, Single Screw Extruder, Plastic Recycling Extruder, Two Stage Extruder, Lab Scale Extruder, Mixing and Feeding Machine, Cooling and Pelletizing Machine, Crushing Machine and so on.