Material Drying
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PA66 hydrolysis strength deterioration
Problem Phenomenon
Product impact/tensile strength drops sharply, no obvious appearance abnormality, batch breakage during use.
Cause Analysis
Water-containing PA66 hydrolyzes at high temperature, molecular weight drops irreversibly; research shows that moisture exceeding 0.2% causes obvious bubbles, silver streaks and performance deterioration; hydrolysis has no appearance characteristics and is a hidden failure.
Solution
①Dry to moisture <0.1%~0.15%; ②verify moisture content compliance by the Karl Fischer method; ③use opened material within a limited time (48~72 hours) or re-dry; ④dried material must not be left open to prevent secondary moisture absorption; ⑤shorten melt residence time in the barrel to reduce heat accumulation degradation.
Key Takeaway
PA66 hydrolysis='invisible performance killer': normal appearance does not mean qualified; high-temperature nylon hydrolyzes faster and more covertly, moisture content verification and time-limited use are life-saving measures.
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