Exploring ways to improve hydrophilic properties on film surfaces

Challenges

We searched for a new coating formulation, but were unable to meet the desired standards...

Company C's functional film has a hydrophilic surface, which allows water droplets on the surface to spread freely. This allows the product to exhibit functions such as "anti-fogging" to prevent water droplets from forming and obstructing visibility, "anti-fouling" to make surface dirt easier to wash off and to prevent water stains and other contaminants from adhering, and "anti-static."

This time, Company C's research laboratory wanted to further improve the hydrophilicity of the film surface, thereby making it more durable against wiping and washing.

Mr. S, the person in charge, looked back on the development status as follows:
"Our company previously applied a coating agent containing a hydrophilic agent such as a surfactant. However, with this method, we found that the hydrophilic agent was removed when wiping or cleaning, resulting in a decrease in hydrophilicity," says Mr. S.

Therefore, the laboratory decided to solve the problem by experimenting with various formulations of coating agents.

The first thing we considered was adding water-soluble polymers such as PVA (polyvinyl alcohol) or PEG (polyethylene glycol) to the coating agent, but this method did not provide sufficient hydrophilicity to the film surface, making it impossible to ensure durability.

Next, we considered blending inorganic particles such as silica particles into the coating agent. Although this improved the hydrophilicity of the film surface, the blending process was not very effective under certain conditions, resulting in issues such as aggregation and particle settling, as well as the risk of particles falling off the film over time.

We also considered adding hydrophilic organic microparticles, but this would increase the viscosity of the coating agent, making it impossible to increase the amount of microparticles added, and the improvement in hydrophilicity was not sufficient.

The team members repeatedly produced prototype films, changing the additives and compounding methods used in the coating. However, they were still far from developing a coating technology that would meet the expected standards. With no breakthrough in sight, the deadline for developing a new product was fast approaching.