Strict monitoring of raw paperboard moisture levels is the foundation of preventing board warp and ensuring sharp, flawless offset printing ink transfers.
1. Ideal Moisture Parameters for Raw Paper rolls
Paperboard is a hygroscopic material composed of natural wood pulp fibers, making it highly sensitive to ambient humidity. Raw paper rolls must maintain optimal moisture levels:
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Target Standards: Ranging between 6% and 9% of dry weight.
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Risks of Out-of-Spec Moisture: Moisture exceeding 10% softens the fibers, leading to weak flute corrugations and smeared offset printing ink. Moisture below 5% renders paper brittle, leading to surface cracking during thermal preheating or creasing.
2. Technical Methods of Moisture Auditing at Chau Thai Son
Chau Thai Son's IQC team employs two scientific moisture testing methods:
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Non-Destructive High-Frequency Meters: High-frequency handheld scanners are pressed against paper rolls to deliver instant moisture readings within 3 seconds without tearing or damaging paper liners.
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Loss on Drying (LOD) Gravimetric Testing: A small sample of paper is cut, weighed, dried inside a calibrated oven at 105°C, and weighed again. The weight differential provides a highly accurate moisture percentage, serving as our benchmark for raw material verification.
3. Warehouse Storage and Environmental Control Rules
To shield sensitive kraft paper rolls from industrial atmospheric humidity:
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Optimized Warehouse Storage: Storage sheds are designed with thermal insulation roofing. All paper rolls are placed vertically on ISPM-15 certified acacia or pine wood pallets, kept 20cm off the floor and 50cm away from walls.
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Free Structural Mockups: Consistently controlled paper moisture ensures that Chau Thai Son's box mockups and packaging products maintain perfect structural lines, giving B2B clients absolute confidence.
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