Douglas D. Keller
Papers # 2018 Las-Vegas
This paper describes the successful collaboration of a regulator, pipe producer and PE material supplier to demonstrate the conformance of pipes produced with inline extrusion compound to the requirement of the Chilean water pipe normative NCh398/1.Of2004 and also to the performance requirements of ISO 4427:2007 parts 1, 2 & 5. The study also highlights the need to carefully consider the design of the system that combines natural compound plus coloring master batch as well as the extruder and screw design in order to properly disperse the carbon black (or any other pigment) into the natural compound during inline extrusion.
Cooperation between the regulator, Centro de Estudios de Medición y Certificación de calidad (CESMEC), pipe producers and a PE material supplier has contributed to Chile’s allowance for the use of natural compound plus black masterbatch for the inline extrusion compound for the production of potable water pipes. An inline extrusion process involves the blending of natural (unpigmented) pellets and black masterbatch pellets, at a specified ratio, where the melt blending of the two components occurs in the extruder producing the pipe. In a 2011 meeting between the regulator and seven pipe producers in Chile, it was communicated that the inline extrusion process would be allowed if test data confirmed that pipe made from this process met the requirements of the Chilean normative NCh398/1.Of2004.
This paper discusses the cooperation between the regulator, pipe producers and a polyethylene material supplier to manufacture inline extruded pipe and demonstrate the ability of two different formulations of natural compound plus black masterbatch to meet the material and pipe properties of NCh398/1. Data demonstrating performance of the inline extrusion produced pipes will be provided as well as a comparison of acceptable and unacceptable methods for blending the natural and black masterbatch pellets prior to inline extrusion production of pipes.
