Metallized Paper Alkali Penetration Test
Metallized Paper Alkali Penetration Test
Purpose:
To test the alkali permeability of metallized paper and evaluate whether beer labels can be easily removed during the alkali washing process.
Test Tools:
• 1–2% NaOH solution
• Glass beaker
• Constant-temperature water bath (60 ± 2 °C)
• Tweezers, timer
• Distilled water (for rinsing)
• Flat tabletop
Test Procedure:
1. Cut a metallized paper sample approximately 5 × 5 cm in size.
2. Heat the 1–2% NaOH solution to 60 °C.
3. Place the sample into the alkali solution (with the metallized side facing up) and soak for 3 minutes.
4. Observe whether the alkali solution permeates appropriately without aluminum layer peeling, delamination, or damage.
Ideal Condition:
The aluminum layer remains intact, the back side shows moderate discoloration, the alkali solution penetrates properly, and the label can be smoothly removed during alkali washing.
