Extrusion & Post
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Thermal aging performance of polyolefin plastomer PPR pipes not meeting standard (Variant: strengthened measures)
Problembeschreibung
The mechanical properties of PPR/PP-R pipes decrease significantly after thermal aging, and the oxidation induction time is insufficient.
Failure of thermal aging performance to meet standards shortens pipe service life and is especially critical in hot water systems.
Especially on the original basis, additional attention is needed, and this problem is more prominent and requires key attention.
Ursachenanalyse
(1) Antioxidant content in raw material insufficient or type improper
(2) Extrusion temperature too high, antioxidant decomposed and consumed
(3) Too much regrind used, antioxidant content low
(4) Pipe use temperature exceeds design temperature
(5) Heat stabilizer addition insufficient to meet 110°C test requirements
(6) On the original basis, additional attention is needed: process parameter fluctuations or equipment state changes aggravate this problem
Lösung
(1) Select PPR special material with sufficient antioxidant
(2) Control extrusion temperature at 200-220°C to avoid thermal decomposition of antioxidant
(3) Control regrind ratio not exceeding 15%
(4) Ensure hot water system temperature is within the design range (generally 70°C water supply)
(5) Add hindered phenolic and phosphite antioxidant combination if necessary
(6) And strengthen process monitoring; on the original basis, additional attention is needed, paying special attention to parameter stability
Wichtigste Erkenntnis
Failure of thermal aging performance to meet standards is caused by insufficient antioxidant system, and needs to be solved from formulation and processing temperature control.
Targeted preventive measures need to be taken in different production scenarios.
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