Interview development engineers

Development of Non-Silicone Release Liner

Could you please introduce yourselves briefly?

Development engineer S

I joined the company in April 2014. Initially assigned to the technical section , I was responsible for this product. In September 2022, I was transferred and currently belong to the quality control section.

Development engineer I

Since joining in April 2018, I have been part of the technical section.

Could you explain where and how non-silicone release liners are used and their applications?

Development engineer S

Non-silicone release liners are mainly used in the field of electronic parts, such as protecting the adhesive side of polyimide films with adhesives used in flexible printed circuit (FPC) boards. Using silicone-based release liners containing silicon can cause silicon to migrate into the adhesive, potentially leading to conductivity issues in the finished FPC boards. Therefore, non-silicone release liners are adopted.

How did your company approach the development of this product?

Development engineer S

During my time in the Technical Department, we faced issues where the release liner would become harder to peel over time (known as heavy release). This was due to reactions between the release agent and the adhesive. We discovered that unreacted components remaining on the surface of the release agent layer were causing this issue. By applying appropriate heat during manufacturing, we ensured complete reaction of the release agent, preventing heavy release.

However, since polyethylene resin is used as a barrier layer in the release liner, excessive heat could cause it to foam or melt, compromising surface smoothness and causing curling. To address this, we considered adding a small amount of another additive to react with the remaining unreacted components, eliminating them without applying excessive heat.

We also had to ensure that the added amount was optimal; too little would leave unreacted components, while too much would hinder the original reaction of the release agent. Through trial and error, we determined the appropriate amount, resulting in a release liner that maintained its appearance and performance without heavy release during customer use.

What challenges did you face during this development?

Development engineer S

One challenge was finding an additive that would react at lower temperatures suitable for our manufacturing conditions and prevent heavy release. We tested various additives and eventually identified a suitable material. Another challenge was determining the optimal amount of additive; too little would leave unreacted components, and too much would interfere with the release agent’s reaction. Finding this balance was difficult but rewarding once achieved.

By adding the optimal amount of the selected additive, we developed a release liner that maintained its appearance and performance without heavy release during customer use.

This technology was also patented, correct?

Development engineer S

Yes, we applied for a patent in 2016 (Japanese Patent Application 2018-089955).

Development engineer I, could you tell us about the recent developments in non-silicone release liners following this project?

Development engineer I

Previously, our lineup of non-silicone release liners was limited, which sometimes made it difficult to meet customer demands. To address this, we expanded the types of release agents used and enhanced our product lineup. We collaborated with release agent manufacturers to develop new products together.

What challenges did you encounter during this expansion?

Development engineer I

Different types of release agents have varying properties and concentrations, so selecting suitable diluents and determining appropriate coating amounts were challenging. We also had to ensure that the release liners performed well and that the manufacturing conditions did not overly burden the workers. These considerations required daily effort and adjustments.

Finally, could each of you share your future outlook?

Development engineer I

We now have a lineup of non-silicone release liners covering various release peel strengths. Moving forward, we aim to continue responding to customer needs effectively.

Development engineer S

From my current perspective in the quality control section, I believe that maintaining and improving daily quality leads to customer satisfaction. I hope to contribute to the production of high-quality products.

Thank you very much.