WANLONG
In addition to distinguishing stone sealers by appearance, smell, pH value, and composition, their effectiveness in use should also be considered.
Generally, breathable sealers do not alter the original color of the stone, and the active ingredients remain stable for several years. However, in practical applications, if the main chain of the functional group is not properly paired or if chemical principles are not followed, the sealer’s lifespan may be significantly reduced or even have the opposite effect.
Silicone or fluorosilicone-based products typically require at least 24 hours after application to achieve protective effects. The chemical reaction completes after 7 days, and the product can be used normally. Some pure fluorinated compounds may allow use just minutes after application, with the chemical reaction completing within 48 hours, while others may take around 7 days to fully react. The quality of the sealer can also be judged based on the following aspects:
1. Color Change of the Stone After Application: The stone should not change color; a color change is unacceptable (unless specifically intended).
2. Water Bead Test: After application, water droplets should form on the dry surface of the stone, which is considered acceptable.
3. Water Droplet Test: Drop multiple water droplets on the treated stone and observe the trace left after wiping the droplet off an hour later. Alternatively, observe how quickly water droplets naturally disappear from stones treated with different sealers—the sealer with the quickest disappearance shows better water-repelling performance.
4. Alkaline Solution Test: Drop a 5% NaOH or 10% NaOH solution on the treated stone and observe how long it takes for the water droplet to disappear and the resulting trace. The longer the time and the lighter the trace, the better the protection.
5. Oil Bead Test: Similar to the method in point 4, but using oil instead of water.
6. Immersion Method: Place stones treated with different sealers in water and observe how quickly the color darkens—the faster the darkening, the worse the protection.
7. Absorption Rate Ratio: After applying the sealer, the stone should have a relatively low absorption rate, but this is a transient value. The slower the increase in absorption rate, the better the waterproofing effect—i.e., the lower the absorption rate, the better the protection.
8. Simulated Application Conditions: Perform small-scale tests simulating various construction conditions, such as dry hanging, wet bonding, water splashing, oil splashing, alkaline water splashing, mud splashing, ultraviolet light exposure, and 80°C baking, followed by measuring the absorption rate.
