Interview development engineer

Perforation Technology

First, could you please introduce yourself briefly?

Development engineer K

I have been in this company for 27 years. Throughout my tenure, I’ve worked in various departments, including Quality Control and Manufacturing Technology. Currently, I’m.in part of the Technical Department I belong to the technical section. The “Perforation” technology we’re discussing was a project I undertook while in the Manufacturing Technology section Department.

In which fields and for what needs is the product using perforation technology applied?

Development engineer K

We developed release liner for adhesive films used on automobile exteriors, particularly for the pillars (window frames). This release liner caters to the demand to replace traditional painting with films. (This release liner is designed to meet the requirement for alternative methods to traditional painting). The adhesive film is produced by applying adhesive onto the release liner, heating it in an oven to evaporate solvents, and then laminating it with a film substrate.

Since the film replaces traditional painting, it requires a high degree of smoothness. This smoothness is essential not only for the film substrate but also for the adhesive and the surface of the release liner used during adhesive application.

Could you elaborate on why smoothness is required for the release liner in paint-substitute films?

Development engineer K

During the manufacturing process, when heat is applied, moisture in the base paper of the release liner vaporizes. However, since both sides of the release liner are coated with polyethylene, the steam has no escape route. The heat softens the polyethylene layers, and the steam accumulates in areas where the adhesion between the base paper and polyethylene is weak, causing the polyethylene to bulge like a balloon. This leads to issues like foaming and pinholes, which compromise surface smoothness and cause problems like adhesive foaming.

Is the “Perforation” technology developed to overcome these issues?

Development engineer K

Yes. we aimed to find a way to allow the moisture in the base paper to escape effectively. We decided to create shallow, small holes in the polyethylene layer on the moisture-barrier side, without penetrating through the release liner, to allow steam to escape to the moisture-barrier side.

What challenges did you face during the development?

Development engineer K

The main challenge was that physically creating holes led to protrusions (indentations) on the opposite release surface, compromising smoothness. The difficulty was in finding a roll that could create physical holes without penetrating through, thus maintaining the smoothness of the release surface.

We tried various methods, but physical marks remained on the opposite side. After further investigation, we found that the protrusion shape made by Company N was most suitable, allowing us to complete our product.

Was there a lot of trial and error before arriving at Company N’s protrusion shape?

Development engineer K

Company N isn’t a roll manufacturer but specializes in etching to create protrusion shapes. We thought their method might work for our needs, and it turned out to be successful. We brought a sample where protrusions were made on a plate via etching, and multiple plates were attached to a roll to create a perforation roll. It was a unique method, but it resulted in the ideal release liner.

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Did you face any difficulties in practical implementation?

Development engineer K

Yes. we had to install this perforation roll onto the existing production line, and fitting it into the limited space was the most challenging aspect.

Ensuring uniform perforation across the width must have been challenging as well…

Development engineer K

Indeed. we brought a sample with actual perforations. The holes were not visible to the naked eye, so we dyed the paper to make them noticeable. As you can see, numerous holes are uniformly perforated across the entire surface. This uniformity is achieved through appropriate processing conditions, such as selecting the right backup roll and applying suitable pressure.

Finally, could you share a message from the development engineer perspective regarding this development?

Development engineer K

As a result of developing the perforation technology, we obtained a patent (Patent No. 6534961). We started this project in 2014, filed for a patent in 2016, refined the specifications, and began sales in 2018. It was beneficial that we could implement this without significant capital investment. Lastly, this technology was not developed by me alone; it was made possible with the cooperation of many individuals. I would like to take this opportunity to express my gratitude to everyone involved. Thank you very much.

Thank you very much.