In recent years, there have been increasing applications of paper carton containers with a spout plug attached. In their early days, the majority of these containers used to have a pull ring to open the spout. In order to improve convenience and reduce environmental impact, we began developing a spout without a pull ring yet maintaining the same sealing performance and ease of opening. In response to customer requests, we also emphasized the touch sense and sound when the bridge (the component connecting the band and cap body which is detached upon opening) detaches. This is to enhance the container’s tamper-evident characteristics which help to clearly verify that the cap is opened for the first time. Following the launch of this new type of cap with a standard diameter of 26 mm, we moved on to develop the product with a medium diameter of 30mm. For this purpose, it was necessary to reduce the height of the spout plug so it would not protrude from the carton body. Therefore, the grooves on the side of the cap were shaped to enhance gripping performance.

Unique seal profile to ensure both ease of opening and sealing performance

For paper cartons with a roof-like profile at the top (gable top), the spout plug is attached to the “roof” section and hence cannot be opened by gripping the entire cap as in the case with PET beverage bottles. Therefore, they required a cap that is even easier to open by pinching with fingertips. To ensure good sealing performance without a pull ring, we adopted the inner ring sealing method widely used by us for PET beverage bottles. However, introducing a sealing structure similar to a conventional cap would require greater force to open. To overcome this challenge, we have adopted a unique sealing mechanism with the cap contact ring adjacent to the spout pushing against the top surface of the spout nozzle and deflecting the latter upon closing the cap. This sealing method helped to achieve both ease of opening and sealing performance at the same time.