Introduction of common problems in the production of black masterbatch.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 is the carbon black carrier?
The carrier is a substance that carries carbon black. What kind of raw materials are used for general plastic products, and what raw materials are used for the 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, black masterbatch which uses recycled material as a carrier is also used.
Why does carbon black need 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 of expression is 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 not many enterprises that use a large amount of products such as white oil or paraffin, which will seriously affect the strength of processed products.
What are the dispersants used in 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, such as drip irrigation products. 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 a 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 it is fatal that calcium carbonate has the effect of accelerating the aging of plastic products.
Does the black masterbatch also need processing aids?
Of course. Smooth processing requires the correct selection of antioxidants, internal lubricants, external lubricants, modifiers and antistatic agents.
What are the processing methods for black masterbatch?
There are three types: single screw method, twin screw method and close love method. Single-screw method: After mixing materials with a mixer, the granulation is carried out 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 a 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%.