We are constantly striving to improve our products to meet the demands of our customers.This time, the three requirements we received and were able to fulfill at the same time were: (1) weight reduction (2) compatibility with highly gaseous carbonated beverages and (3) opening sound.Reducing the weight of the cap can lead to a reduction of several thousand tons of CO2 emissions per year, including a reduction in the amount of raw materials required for its manufacture.
In addition, the new cap has a seal that withstands the recent “strong carbonation” boom, while maintaining the easy-opening of the conventional cap.And yet, there were a wide variety of factors required, such as the opening sound that gives a sense of carbonation.

Maximized pressure resistance performance while reducing weight

Among the various challenges, the first thing we set out to do was to reduce the weight of the cap.
Since the band at the bottom of the cap has little effect on performance, we focused on weight reduction there.On the other hand, the screw in the middle of the cap has been strengthened to prevent the cap from lifting due to the increase in internal pressure caused by strong carbonation.During the development process, we encountered a problem with a reduction in the cap opening noise.After a year of repeated trial and error, we were finally able to determine the cause of the problem and designed a sealing profile that allows gas to escape all at once when the bottle is opened.This is how we were able to develop the lightest carbonated beverage cap in Japan.

In recent years, the seasoning & condiment industry has been seeking to improve the usability of caps, such as ease of pouring and dripping performance, in addition to sealing, which is an essential role of caps.For this reason, silicone valves are increasingly being used for spouts. But the unit cost of the cap is high due to the high cost of the silicone material, the need for a separate part to secure the silicone valve, and the need for a separate device to incorporate the cap. So we changed the valve material from silicone to elastomer, and dissimilar material molding(co-injection,double-shot injection) technology was adopted to enable integrated molding of the valve and cap.This has resulted in the productization of a new valve cap with stable performance and greatly reduced production costs.

Achieves both pourability and dripless performance

A valve cap with a thin wall thickness facilitates valve deformation during dispensing, resulting in a smaller dispensing force and better dispensing performance.On the other hand, thicker valves allow the liquid to be shut off more quickly, resulting in better run-off after dispensing.In order to achieve both of these contradictory abilities, the base of the valve is made thinner and only in the center and where the liquid is cut is made thicker, thereby achieving both discharge and dripping performance requirements.

Recently, Nippon Closures’ technology is helping customers in the civil engineering and construction industries.
Since the Kasago Tunnel collapse accident in 2012, safety awareness has increased at construction sites, and we are checking to see that nuts are tightened to the proper torque.However, this reduced work efficiency and there were cases of forgetting to tighten the bolts due to human error.
Therefore, we were asked if we could develop an attachment that would break when tightened to the proper torque and disengage from the nut.The development of the attachment was started based on the concept that if the attachment was removed, it would prove that the proper torque had been applied and prevent forgetfulness.

Torque management and prevention of forgetting to tighten with a single cap.

It was a completely new industry, and development was also a process of exploration.First of all, the product was to be used outdoors, and the material used for standard caps is fundamentally insufficient in terms of durability and strength.More than 10 different materials were tested to find the best fit, and dozens of product shapes were tested.
Through this process of gradually accumulating know-how, the decision was finally made to commercialize a product that fulfilled the required functions.However, the decision to commercialize the product was short-lived, and a glitch occurred.After about a week of setting the nuts, about 1% of the time, the nuts were damaged without the proper torque.The cause was too strong of a mating* with the nut.We urgently and radically re-looked the mating methods, and at the same time, we constructed a severe test in which the frequency of defect occurrence was more than 90%.After optimizing the mating until zero breakage was achieved in a severe test, the product was successfully productization.

*Mating: A relationship in which various parts of a machine fit together, as in the case of a shaft and bearing. Also, its condition.

As a recent trend of the bottle can market, caps are required to possess the following performance characteristics: (1) ease of opening, (2) impact resistance, and (3) liquid spurts prevention (*1). Especially in Japan, a society with an increasingly aging population, there is strong demand for “easy-to-open” caps. Conventional P.P. caps for bottle cans are usually made by bonding a single layer of liner material to the “aluminum shell” on the top surface (which forms part of the exterior) to protect the interior. However, with this conventional adhesive method, the force required to open the cap is determined by the degree of mating force between the liner material and the bottle opening. This means reducing the mating force in pursuit of ease of opening will lower the sealing performance, resulting in a trade-off between the two.
*1. Liquid spurts: The phenomenon of liquid accumulated inside the cap spurting out when the cap is opened.

Dual layer structure to ensure both ease of opening and sealing performance

Using our proprietary liner mold technology(*2), we have created a liner structure (dual layers) that is easy to open and seals well. By making the aluminum shell and the first-layer liner non-adhesive, the bottle cap would require less force to open. Furthermore, by using a soft, heat-resistant material for the second-layer liner, we succeeded in developing a cap that is easy to open while maintaining high sealing performance. By optimizing the profile of the second-layer liner to reduce the amount of liquid accumulating inside the cap, we successfully managed to reduce liquid spurting when the cap is opened.
*2. liner mold technology: Technology to mold the liner according to a clearly defined profile

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.