I. Initial Tack: Securely adheres immediately. Use the inclined plane rolling ball method (e.g., the CZY-G initial tack tester) to measure the largest steel ball the label can adhere to. The larger the steel ball, the stronger the initial tack. For example, if it can adhere to a size 3 steel ball, the instantaneous tack is good, suitable for automatic labeling.
II. Holding Power: Durable and doesn't peel off. Use a holding power tester to attach the label and hang a weight on it. Observe how long it takes for it to fall off. The longer the time, the better the holding power. For example, if it doesn't fall off after hanging a 500-gram weight for 24 hours, it indicates good long-term fixation.
III. Peel Strength: Effortless tearing. Use a peel tester to measure the peel force at 180° or 90°. The higher the value, the stronger the adhesion. For example, a peel force ≥ 1.5 N/cm indicates a strong enough adhesion and it's not easy to fall off.
IV. Weather Resistance: Environmental Adaptability
Conduct aging tests including high and low temperatures, ultraviolet radiation, and water immersion to check the adhesion retention rate. For example, if the adhesion decreases by ≤20% after 7 days at 70℃ and 85% humidity, it indicates strong environmental adaptability.
V. Residue Test: Clean Removal
After removing the label, check for any adhesive residue. No residue indicates good adhesive quality and no residue.
VI. Third-Party Testing: Authoritative Certification
For higher requirements, have an organization with CNAS or CMA accreditation conduct tests according to ASTM, ISO, GB/T, etc., for more reliable data.
VII. Real-World Testing: Simulating Real-Scenes
Apply the label to real-world environments (e.g., oil stains, curved surfaces) to check for edge lifting or detachment. For example, if the label does not lift after 24 hours on stainless steel, it indicates good real-world performance.
