Antti Tynys, Dongyu Fang, Prashant Nikhade, Mark Yu, Tomi Kangas
Papers # 2016 Berlin
The need for larger diameter pipes and fittings for in-house heating, plumbing and domestic water systems is pushing the existing materials and processes to their limits. More often final products cannot be produced without penalties either in production rate or in final product quality. This paper discusses processability and properties of newly developed PP-R and PE-RT grades. The benefits offered by the new grades in production of pipes and fittings as well as in the final product properties and quality are demonstrated and elaborated.
Propylene random copolymers (PP-R and PP-RCT), polyethylene resins for raised temperature (PE-RT) and crosslinked polyethylene (PEX) are commonly used for inhouse heating, plumbing and domestic water systems. These materials are in high demand, especially in Europe, Middle East and Asia, due to a large number of on-going and planned construction projects. Additionally, more high rise buildings are being built, and consequently pipes and fittings having higher diameters are increasingly needed. Therefore excellent processability of pipe resins becomes essential in order to ensure efficient and economical production of pipes and fittings without forfeiting any of the materials’ excellent properties. To address the market demand and to enable production of pipes and fittings at higher production rates, novel polyolefin materials were developed. These materials show excellent processability in combination with optimised mechanical property profile and enable higher output rates in pipe as well as in fitting production. The higher production rates are achieved without the need for extra cooling or other process adjustments. In this paper, the authors describe processing of PP-R and PE-RT pipes and fittings using newly developed PP-R and PE-RT grades. It is shown that the new materials enable higher pipe production rates without the need for process adjustments compared with conventionally used materials. In particular, the results of large diameter PP-R pipe and fitting production based on machine trials are discussed. It is demonstrated, that the total cycle time in injection moulding of fittings can be shortened by up to 20% and ovality of fittings can be improved by up to 40% when the novel PP-R material is used. Pigment dispersion, shrinkage and other product properties are also discussed in the paper.