We manufacture and market the 25NC-Flap SHA Cap, designed for milk beverage containers in chilled distribution.Our customers have expressed a desire to reduce container weight as part of their efforts to decrease plastic consumption. In addition, recognizing that this initiative aligns with the Toyo Seikan Group’s “Eco Action Plan 2030” and its commitment to achieving a decarbonized society, we launched a development program focused on weight reduction. In our development process, we focused on the following three key points.

1. Achieving weight reduction through combined optimization of the bottle mouth shape and the cap
2. Meeting the same sealing standards as the conventional cap while maintaining ease of opening
3. Keeping the outer diameter of the cap unchanged from the conventional product in order to maintain ease of opening

Achieving both reduced plastic usage and ease of opening!

For weight reduction, we proposed a new bottle mouth and developed a cap to match it. For the bottle mouth, we reduced the height and thinned the wall thickness, achieving approximately 30% reduction in mouth weight. For the cap, we reduced the height and thinned the top panel, achieving approximately 15% reduction in cap weight. Furthermore, by optimizing the knurl pattern on the side of the cap (the textured gripping area), we improved graspability even with the reduced-height cap, successfully achieving both reduced plastic usage and ease of opening.

When we initially conducted performance evaluations using these weight-reduced bottles and caps, inward collapse deformation of the mouth occurred due to the reduction in strength resulting from the bottle weight reduction, making it difficult to maintain the required product performance. Through repeated root cause analysis and testing, we were able to finalize the specifications by reviewing the cap’s seal geometry and establishing appropriate capping conditions.