The Common Problems of Black Masterbatch

Black masterbatch is often used in the field of plastics, thermoplastic elastomer material modification and product processing and molding. Compared with the direct use of carbon black, the use of black masterbatch product is more convenient and environmentally friendly. In this article, we will share with you the common problems of small black masterbatch.

 

What materials are black masterbatch made of?

 

Usually the materials that make up the black masterbatch include carbon black, carbon black carrier, carbon black wetting agent, carbon black dispersant and other processing aids.

 

What carbon blacks are used for black masterbatch?

 

According to the international classification, there are more than 30 varieties of carbon black masterbatches in our country, which are mainly divided into two categories: rubber and non-rubber. Among the rubber carbon blacks, wear-resistant carbon blacks are mainly used, which can effectively improve the abrasion resistance of rubber tires. Among non-rubber carbon blacks, there are only a few types of carbon blacks that can be used as black masterbatches. 

 

Channel carbon black is the most widely used in plastics, mainly due to its abundant source, high purity and small particle size. Among them, it is divided into high pigment carbon black (particle size 9-17mm), medium pigment carbon black (particle size 18-25mm) and low pigment carbon black (particle size 26-37mm). Due to different types of carbon black, the prices vary greatly. Generally carbon black particles seldom exist as primary particles due to their own reactivity, and almost all exist as agglomerated particles with a certain range of particle diameters.

 

What is the carbon black carrier?

 

The carrier is the substance that carries carbon black. Generally, the raw materials used in plastic products are the raw materials used in the carrier. In this way, the black masterbatch manufactured has better compatibility with plastic raw materials. For example, the black masterbatch carrier used in PS (polystyrene) plastic products is PS. For polyethylene plastic products, the carrier is polyethylene. However, LDPE (High Pressure Polyethylene) is generally selected because LDPE has the strongest carbon black carrying capacity and good processing performance.

 

Other polyethylene HDPE and LLDPE can only produce low-concentration black masterbatch. For PP (polypropylene) plastic products, only black masterbatches with PP and LDPE as carriers can be used, but black masterbatches with HDPE, LLDPE and other plastics as carriers cannot be used. The main reason is that the compatibility of PP with HDPE and LLDPE is worse, and it will cause PP to become brittle. Of course, there is also a black masterbatch with recycled materials as a carrier. Of course, general-purpose black masterbatch carriers will be EVA, and the advanced black masterbatch carriers will be other vinyl elastomers with a smaller odor.

 

 Why does carbon black need a wetting agent?

 

Usually the specific gravity of carbon black is about 2g/cm3. Due to the small particle size of carbon black, the apparent density is very small, and it appears fluffy and seems very light. In order to process smoothly, the carbon black must first be wetted. So, the choice of wetting agent is very critical. In order to reduce costs, there are part companies that use a large number of products such as white oil or paraffin, which will seriously affect the strength of the processed products.