Black masterbatch generally has these materials: A. carbon black; B. Carbon black carrier; C. Carbon black wetting agent; D. Carbon black dispersant; E. Other processing aids. Here are some common problems with black masterbatch carbon black:

What about carbon black carrier?

The carrier is the material carrying carbon black. Generally, the materials used for plastic products are determined by the carrier. The black masterbatch thus manufactured has good compatibility with plastic raw materials. For example, PS (polystyrene) plastic products use the black masterbatch carrier PS. For polyethylene plastic products, the carrier is polyethylene. However, LDPE (high pressure polyethylene) is generally selected, because LDPE has the strongest carbon black bearing capacity and good processability. Other polyethylene HDPE and LLDPE can only produce low concentration black masterbatch. For PP (polypropylene) plastic products, only the black masterbatch with PP and LDPE as carriers can be used, but the black masterbatch with HDPE, LLDPE and other plastics as carriers cannot be used. Of course, black masterbatch with recycled material as carrier is also used.

Why does carbon black need a wetting agent?

The specific gravity of carbon black is about 2g/cm. Because the particle size of carbon black is very small, its apparent density is very small, and it looks fluffy and light. To process successfully, carbon black must be wetted first. The selection of wetting agent is critical. In order to reduce costs, there are many enterprises that use white oil or paraffin products in large quantities, which will seriously affect the strength of processed products.

What dispersants are used for carbon black masterbatch?

There are two types of organic dispersants and inorganic dispersants. High grade black masterbatch uses organic dispersant, which is mainly used for plastic products with high environmental requirements, such as drip irrigation products. Low grade black masterbatch uses inorganic dispersant, commonly calcium carbonate. It can be judged from the package of master batch that inorganic dispersant must be used for only half a bag of 25kg; The bag is full of black masterbatch using organic dispersant. The use of inorganic dispersants can greatly reduce the cost of black masterbatch, but it is fatal that calcium carbonate can accelerate the aging of plastic products.

Does black masterbatch also need processing aids?

Certainly. A smooth processing requires the correct selection of antioxidants, internal lubricants, external lubricants, modifiers and antistatic agents.

What are the processing methods of black masterbatch?

There are three methods: single screw method, twin screw method and intimate method. Single screw method: after the materials are mixed with a mixer, they are granulated by the pull rod of a single screw extruder. Generally, the carbon black concentration is 18-20%. The process is backward, and the environmental conditions at the production site are poor. It is an obsolete process. It is not ruled out that some small plants just started still use this method for processing. Twin screw method: after the materials are mixed with a mixer, they are granulated by the brace or water ring of the twin screw extruder. Due to the limited mixing capacity of the twin screw extruder, the carbon black concentration of the master batch is generally 25-32%. Internal mixing method: after the materials are mixed with a mixer, they are added into the internal mixer for kneading, and then fed into the twin-screw extruder by the feeder. The masterbatch is generally 40-45% carbon black through water ring or underwater pelletizing.