Quality Assessments for Bimodal Pipes

Since the ZSK-NT components have been tried and tested worldwide in many applications, there is very little novelty risk . The following describes the typical operating conditions for the two stages. 

Comparative studies of pellet homogeneity for different grades of PE 100 + are given below. The experiments were conducted on ZSK-NT systems of different sizes (ZSK-NT 26/40 and ZSK-NT 50/70). The samples compared originated from different manufacturers using different compounding systems. 

The ISO rating in accordance with ISO 18553 [5] was introduced for carbon black distribution in finished and semi-finished products and permits no particles larger than 60 pm in their largest dimension - corresponding to an ISO rating of 3.0. The reason for this is that large impurities can cause stress peaks which may lead to cracks and mechanical failure. 

White spots are not counted as impurities, because they contain the same material as the surrounding matrix. This method provides poor quality assessments, if the melt already contained stretched particles that would be destroyed at the next stage of processing. Nevertheless, this method is occasionally used to analyze white spots in pellets. This method 

A very fast method with a low standard deviation is based on the total size of the non-pigmented areas in relation to the total area of the section analyzed (White Spot Area-WSA). 

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