Application of black masterbatch in plastic products
09/05/2018
Black masterbatch also has a very important position in the molding of plastic
products. Black masterbatch can be used for dyeing, for anti-aging, for
conductive articles and the like.
1. What materials are the black masterbatch made up of?
The materials constituting the black masterbatch are: A. carbon black; B.
carbon black carrier; C. carbon black wetting agent; D. carbon black
dispersant; E. Other processing additives.
2. Please introduce carbon black for black masterbatch.
According to the international classification, there are more than 30 varieties
in China. Mainly divided into two categories of rubber and non-rubber. In the
carbon black for rubber, it is mainly wear-resistant carbon black, which can
effectively improve the wear resistance of the rubber tire; in the non-rubber
carbon black, there are only a few kinds of carbon black which can be used for
the black masterbatch. The grooved carbon black is most widely used in
plastics, mainly due to its abundant source, high purity and small particle
size.
3. What is the carbon black carrier?
The carrier is a substance that carries carbon black. The kind of raw materials
the general plastic products use is what used as carrier. The black masterbatch
thus produced has good compatibility with the plastic raw material. For
example, PS (polystyrene) plastic products, the black masterbatch carrier used
is PS.
For polyethylene plastic products, the carrier is polyethylene. However, LDPE
(high pressure polyethylene) is generally used because LDPE has the strongest
ability to carry carbon black and has good processing performance. Other
polyethylene HDPE and LLDPE can only produce low concentration black
masterbatch. For PP (polypropylene) plastic products, only black masterbatch
with PP and LDPE as the carrier can be used, but black masterbatch with HDPE
and LLDPE and other plastics as the carrier cannot be used. Of course, the
black masterbatch which uses the recycled material as a carrier is also used.
4. Why does carbon black require a wetting agent?
The carbon black has a specific gravity of about 2 g/cm. Since the carbon black
has a small particle size, the density appears small and appears fluffy and
seems to be very light. To process smoothly, the carbon black must be wetted
first. The choice of wetting agent is critical. In order to reduce costs, there
are many enterprises that use a large amount of products such as white oil or
paraffin, which will seriously affect the strength of processed products.
5. What are the dispersants used in the carbon black masterbatch?
There are two types of organic dispersants and inorganic dispersants. The
high-grade black masterbatch uses an organic dispersant, which is mainly used
for the use of plastic products with high environmental requirements. The
low-grade black masterbatch uses an inorganic dispersant, usually calcium
carbonate. It can be judged from the masterbatch packaging that 25 kg of only
half bag is definitely an inorganic dispersant; full bag is a black masterbatch
using an organic dispersant. The use of inorganic dispersants can greatly
reduce the cost of black masterbatch, but unfortunately calcium carbonate has
the effect of accelerating the aging of plastic products.
6. Does the black masterbatch also need processing additives?
Of course you need it. To complete processing successfully requires the correct
selection of antioxidants, internal lubricants, external lubricants, modifiers
and antistatic agents.
7. What are the processing methods for black masterbatch?
There are three types: single screw method, twin screw method and dense method.
Single-screw method: After mixing materials with a mixer, the granules are
granulated by a single-screw extruder. The concentration of carbon black is
generally 18-20%, the process is backward, and the environmental conditions at
the production site are poor. Some small starters still use this method to
process.
Twin-screw method: After mixing materials with a mixer, it is granulated by a
twin-screw extruder or a water ring. Due to the limited mixing capacity of the
twin-screw machine, the masterbatch generally has a carbon black concentration
of 25-32%. Mixing method: After mixing the materials with a mixer, kneading by
adding an internal mixer, feeding the twin-screw extruder by a feeder, and
cutting the pellets by water ring or underwater, the masterbatch generally has
a carbon black concentration of 40- 45%.
8. Does the processing method have an effect on the performance of the
masterbatch?
Yes. Obviously, the mixing method increases the carrier's ability to carry
carbon black while the carbon black can enter the carrier more uniformly. The
mechanical kneading advantage of the internal mixer is utilized to break up the
agglomerated particles, so that the agglomeration particle size of the carbon
black particles is greatly reduced, and due to the particle size and
distribution of the carbon black in the master batch are uniform, it cannot be
replaced by the other two methods.
9. In what aspects does the black masterbatch have outstanding performance?
In the dyeing of plastic products, the black masterbatch only needs 0.6%-0.8%,
it will be very dark, and it will not be darker if it is added.
According to the test data, if the products used outdoors in Xinjiang need to
rely on black masterbatch to prevent aging, just use high-quality black
masterbatch (rather than returning material as carrier, white oil wetting,
calcium carbonate dispersion, etc.) The content of carbon black in the product
reaches 2-2.5%, the product life can reach more than 10 years. This is why drip
products, water products, and communication cable products are all black. In
addition, carbon black has a special contribution to the strength of the
product and the enhancement of conductivity.
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