Six key points to determine the quality of black masterbatch
08/13/2018
First, the dispersion is high
Black masterbatch is produced using carbon black. High-load black masterbatches produced using single or double screw extruders have very poor dispersion. When
the end user mixes or molds these black masterbatch, its performance is
only slightly better than carbon black, but the effect is equally
unsatisfactory. In
order to achieve a stable high degree of dispersion, a high level of
shearing kneader must be used to mix carbon black. With sufficient strength, these mixers allow the carbon black and base resin to be thoroughly mixed together. The type of carbon black used also affects the coloring dispersibility. The smaller the carbon black particles, the more difficult the dispersion is.
Second, the coverage is strong
The
second factor determining the quality of the black masterbatch is the
coverage. This factor is especially important for masterbatches used in
scrap or recycled polymers. In these cases, the role of black is to
cover the rest of the scrap colour. The
large-particle carbon black has a poor coloring ability and is not easy
to cover all other colors in the lower layer, and as a result, the
final product only obtains a deviation from the color. In the melting process, the ability to correctly select the carbon
black with high coloring ability to cover the existing color is the
so-called covering power.
Third, the liquidity is better
The third factor determining the quality of the black masterbatch is rheology and fluidity. If
a masterbatch itself has good dispersibility, but it cannot flow into
the material to be molded, the production effect is not satisfactory. In general, primers used to produce masterbatches have higher rheology. In order to save costs, some masterbatch producers use recycled materials, scraps or recycled materials as resin carriers. The
flow properties of the masterbatch thus produced will be significantly
reduced, and if the rheology is not good, the mold union will have
trouble with the cycle time and appearance treatment. It
is worth noting that if the dispersion and rheology are not high, some
end users will make up for it by increasing the dilution ratio, but this
will only increase the cost of using the masterbatch. The masterbatch with the smallest dilution ratio produces a uniform, dispersive black.
Fourth, the compatibility is greater
The size of the compatibility is the fourth factor determining the quality of the black masterbatch. If the masterbatch is produced using chips or recycled materials, it may contain contaminants or other non-meltable polymers. This can cause some unpredictable and difficult constraints, wasting the time and raw materials of the final consumer. At
this time, the base resin can be used to produce high quality
masterbatch, and the masterbatch has good compatibility during the
melting process. Premium masterbatches can be produced using LLDPE, LDPE, HDPE, PP, PS, PA, and other materials. Special polymer masterbatches are available if engineering grades and stringent physical properties have been noted. Several
internationally large masterbatches producers are conducting research
to produce so-called "global universal" masterbatches. These masterbatches are widely compatible with other raw materials, have good rheology, and are flexible for application.
Fifth, the stability should be consistent
In
today's international economy, international customers are absolutely
necessary for the quality of masterbatch and the stability of raw
materials, which is the fifth factor determining the quality of black
masterbatch. One of the main manifestations of stability is the smooth carbon black ratio. If
the percentage of carbon black is fluctuating, the amount of
masterbatch to be melted is not the same, and it is impossible to
produce a product of the same hue. Some
final producers report that during the production process, the required
dilution ratio is usually 5-8%, which is obviously unacceptable. Of course, other factors such as the fluidity and dispersion of the
injected melt should be consistent with the amount of charge per batch.
Sixth, the brightness should be clearly defined
The final factor in determining the quality of the black masterbatch is the shade of the color. There
are various carbon black types available on the market for the
coloration of masterbatch, but the color and price of each type are also
very different. Large particle carbon black has a lower degree of coloration and a different background color than small particle carbon black. Large-grain
masterbatches are suitable for use in film production such as garbage
bags, but are not suitable for the production of products that are
aesthetically pleasing, such as television signage or where UV
protection is required, such as agricultural film or external piping. For these products, only the use of high-priced small particle carbon black is used. In addition, low transparency is also a special feature of small particle carbon black.
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