Can water-based ink withstand 75% rubbing alcohol?
Date: Nov 12 2024 From: Star Color
With the heightened awareness of environmental protection, an increasing number of printing enterprises are transitioning to water-based inks. In practical applications, the tolerance of water-based inks under various chemical environments, particularly their resistance to alcohol, often becomes a topic of discussion among users, especially in specific scenarios such as areas requiring disinfection with 75% alcohol. If water-based inks cannot withstand this, they may fade, leading to the question: Are water-based inks inherently unable to tolerate alcohol?
Analysis of Water-Based Ink's Resistance to 75% Alcohol
- The Impact of Alcohol on Water-Based Inks
75% alcohol, a commonly used concentration for daily cleaning and disinfection, possesses strong solubilizing properties and can dissolve many organic compounds, posing a significant challenge to water-based inks. The resins, additives, and pigments in water-based inks may undergo the following phenomena under friction from high-concentration alcohol:
- Ink layer softening or dissolution: The resin in water-based inks can easily soften in alcohol, causing the ink layer's surface to become sticky or even dissolve, thereby affecting the clarity and durability of the pattern.
- Color fading: High-concentration alcohol may destroy the pigments in the ink, resulting in color fading or distortion.
- Decrease in adhesion: Even after sufficient curing, water-based inks may exhibit weak adhesion on smooth surfaces and are prone to detachment under alcohol friction.
- Actual Test Results
To verify the performance of water-based inks under friction with 75% alcohol, the following test can be conducted:
Step 1: Select printed and fully dried water-based ink samples.
Step 2: Use a cotton cloth or alcohol wipe soaked in 75% isopropanol and apply appropriate pressure to rub repeatedly.
Step 3: Observe the condition of the ink layer after wiping to check for dissolution, fading, or adhesion loss.
Based on industry testing experience, most water-based inks will exhibit varying degrees of fading and softening under these conditions and cannot fully resist friction from 75% isopropanol.
How to Improve Water-Based Ink's Alcohol Resistance?
Although water-based inks inherently have weaker alcohol tolerance due to formula limitations, their resistance to alcohol can be enhanced to a certain extent by adjusting the formula and printing process. Here are some common solutions:
- Improve the Formula of Water-Based Inks
- Use high solvent-resistant resins: Consider selecting resins with higher chemical resistance, such as polyurethane (PU) or modified acrylic resins. These resins have higher tolerance to alcohol while improving the ink's adhesion and flexibility.
- Add crosslinkers: Introducing crosslinkers, such as isocyanates, into the ink can form a denser network structure after drying and curing, thereby enhancing the ink layer's chemical resistance.
- Optimize additive formulations: Add alcohol-resistant additives to enhance the ink layer's stability and abrasion resistance.
- Adopt Surface Coating Treatment
- Clear coat application: After printing, a layer of transparent water-based clear coat or UV clear coat can be applied as a surface coating. This treatment not only enhances alcohol resistance but also improves the product's waterproofness and scratch resistance.
- UV curing treatment: If the process permits, consider using UV-curable inks or adding a UV coating over the water-based ink to significantly improve chemical resistance.
- Improve Printing and Curing Processes
- Increase curing temperature and time: Ensure that the water-based ink undergoes sufficient curing to make the ink layer more solid and stable.
- Control coating thickness: Appropriately increasing the ink layer's thickness can increase its resistance to external chemicals, but avoid excessive thickness that may affect drying speed.
Currently, Zhongzhixing has developed a flexographic water-based ink that can tolerate 75% alcohol. When printed on paper or plastic film, it will not fade after alcohol wiping. If you are interested, please contact us.
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