Extrusion & Post
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Random copolymer polypropylene pipe special material (Nordic standard） PPR pipe thermal aging performance substandard
Problem Phenomenon
After thermal aging, the mechanical properties of PPR/PP-R pipes decline significantly, and the oxidation induction time is insufficient.
Substandard thermal aging performance shortens pipe service life, especially critical in hot water systems.
Cause Analysis
（1）The antioxidant content in the raw material is insufficient or the type is improper\
（2）Extrusion temperature too high, the antioxidant decomposes and is consumed\
（3）Too much regrind used, antioxidant content low\
（4）Pipe use temperature exceeds the design temperature\
（5）The heat stabilizer addition is insufficient to meet the 110°C test requirements
Solution
（1）Select PPR special material containing sufficient antioxidant\
（2）Control the extrusion temperature at 200-220°C to avoid thermal decomposition of the antioxidant\
（3）Control the regrind ratio, not exceeding 15%\
（4）Ensure the hot water system temperature is within the design range (generally 70°C water supply)\
（5）If necessary, add a combination of hindered phenolic and phosphite antioxidants
Key Takeaway
Substandard thermal aging performance is caused by an insufficient antioxidant system, and needs to be solved from formulation and processing temperature control.
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