1. Key Performance Test Standards
Labels must pass the following basic tests to be considered qualified:
Water Immersion Test
Qualification Standard: After completely immersing the label in room temperature water for 24-72 hours, remove and dry it. There should be no delamination, bubbling, edge curling, or peeling. The printed content should be clear and unfaded.
Advanced Requirements: If used in high-temperature cleaning processes, it must remain stable after immersion in 60℃ hot water for at least 30 minutes.
Wet Adhesion Test
Qualification Standard: After being wet or immersed in water, the label should still adhere firmly to the target material surface such as metal or plastic, without automatic detachment or edge curling.
Professional Reference: A 180° peel strength test can be used. Ideally, the adhesion strength should decrease by no more than 30% before and after water immersion.
Rubbing Durability Test (Wet State)
Acceptance Criteria: After immersing the label in water, rub it 10-20 times with a damp cloth under moderate force. The printed image should not peel off or become blurred. Especially for heat transfer labels, resin ribbon printing should be used to ensure scratch resistance.
Environmental Adaptability Test
Humidity and Temperature Cycling Test: After being placed in an environment of 85% RH and 60℃ for 48 hours, and then returning to room temperature, the label should show no adhesive layer failure or deformation.
Thermal Shock Test: After cycling between -20℃ and 60℃ 3 times, the label should not peel off or crack.
2. Reference Protection Rating and Industry Standards
IP Protection Rating:
IPX4 (Splash Protection): Suitable for general humid environments.
IPX7 (Short-Term Immersion): Can be immersed in 1 meter of water for 30 minutes. Suitable for metal can labels during cleaning processes.
Material and Process Standards: PET or PVC are preferred materials; avoid using coated paper with only a surface coating.
Seams should be free of tears, and cut surfaces should show no signs of water seepage. Acrylic pressure-sensitive adhesive is preferred.
✅ Comprehensive Judgment: A qualified waterproof label must meet all standards in tests including water immersion, wet adhesion, friction, and temperature and humidity changes, and must meet the protection level requirements of the actual application scenario. Simply stating "it's fine as long as it doesn't get wet" is insufficient for qualification; systematic verification is necessary.
