Pet bottle utilizing sealing principle of spherical body and conical body inner surface, and cap of pet bottle

Abstract

[Problem] A conventional PET bottle and a cap thereof cannot be geometrically brought into close contact with each other, and thus, there have been provided sealing methods in which the material of the cap is configured to be softer and a gap from a bottle mouth is flattened due to deformation of said material during fastening; however, such methods involve producing the cap of the PET bottle using a material that deforms more readily than the bottle, such as PE. These conventional methods are disadvantageous in terms of recycling and design properties not only because force for deforming the cap material is required in opening and closing the cap but also because the materials of the cap and the bottle are different. [Solution] The present invention presents a structure of a PET bottle and a cap thereof with which it is possible to easily seal even materials that do not readily deform, and with which it is possible to carry out sealing using less fastening force, by applying a geometrically sealable structure of contact between a spherical surface and a conical inner surface. Thus, the cap can be produced using the same PET material as the PET bottle.

Description

Plastic bottle and its cap utilizing the sealing principle between a sphere and the inner surface of a cone

[0001] The present invention relates to a cap for a sealed container and its sealing technology, and particularly includes a technical field focused on the cap structure of a plastic bottle.

[0002] Conventional plastic bottle caps achieve sealing by making caps using plastics such as softer PE (polyethylene) for the bottle necks made of hard PET materials. In this method, the gap between the cap and the bottle neck is sealed by deforming the cap material by the tightening force of the cap to fill the gap. Therefore, a certain amount of force is required to open and close the cap, making it difficult for elderly people or children with weak grip strength to operate.

[0003] Also, since the materials of the cap and the bottle are different, there is also the problem that it takes time during recycling.

[0004] Regarding the sealing problem of containers such as plastic bottles, since ancient times, there has been a traditional method of sealing hard materials such as pots, cans, and bottles with a cloth-wrapped stopper and covering it with a soft material. Even now, soft cork bottle stoppers, soft rubber covers for pots, covers for glass bottles, and soft sealing materials for metal joints are used, but these sealing methods are an extension of ideas based on traditional thinking.

[0005] Geometrically considered, theoretically, when a stopper is used to seal the cylindrical bottle neck of a container, it is an essential condition that the diameter of the contact part between the inner diameter of the bottle neck and the outer diameter of the stopper is the same and coaxial. When covering and sealing the bottle neck surface of the container, it is essential that the bottom surface of the cover and the upper surface of the bottle neck (pot mouth) overlap parallelly, but both are difficult to achieve in reality.

[0006] Therefore, conventional plastic bottle caps need to be crushed by deforming the cap material with the tightening force of the cap to eliminate the gaps caused by geometric reasons and manufacturing deviations for sealing. This is the reason why more force is required to open and close the cap.

[0007] WO2010058596A1

[0008] Conventional methods of sealing PET bottles and caps require the cap and bottle neck to be coaxial or parallel to each other to achieve a tight seal, and furthermore, the cap needs to be deformed to absorb manufacturing errors. In contrast, the present invention aims to provide a method for sealing PET bottles with caps and bottle necks without significant deformation of the caps and necks. Specifically, it proposes easily achieving a tight seal by utilizing the principle of contact sealing between a sphere and the inner surface of a cone.

[0009] Unlike conventional PET bottles and caps that seal by deformation of the cap material, the present invention utilizes the contact principle between a sphere and the inner surface of a cone, allowing for a seal with minimal deformation of the cap and bottle opening. Therefore, the cap can be made from the same PET material as the bottle itself.

[0010] Since the basic shapes of this invention are a cone and a sphere, and are composed of the basic geometric shapes of a cone and a sphere that are easy to process and measure, it is easy to maintain manufacturing accuracy.

[0011] In geometry, one method for sealing two objects is through the contact between a sphere and the inner surface of a cone. In this method, positioning and tight sealing can be achieved simultaneously when the sphere and cone come into contact. The present invention provides a method for easily achieving positioning and sealing by providing a sphere and a cone-like structure at the contact points between the cap and the bottle neck, respectively, so that the contact between the cap and the bottle neck is between a sphere and the inner surface of a cone.

[0012] This invention allows for correct positioning and sealing even if the cap and bottle neck are not coaxial or parallel before closing, as long as the cap fits onto the bottle neck even if it is slightly misaligned, by making contact with the spherical and conical inner surfaces of the contact surface with the bottle neck. This precise positioning and rational contact result in less material deformation than conventional methods, reducing the force required to open and close the cap, and improving the convenience of capping.

[0013] The structure of the present invention reduces the demands on the deformation of the cap, allowing the cap to be made from the same PET material as the bottle. This eliminates the need to separate caps and bottles during PET bottle recycling, saving collection effort, reducing costs, and improving the reuse quality of collected PET in horizontal recycling.

[0014] Since the cap and bottle can be made from the same PET material, a completely transparent PET bottle can be created, improving its design appeal.

[0015] Alternatively, since the requirement for cap deformation has been reduced and caps can be made from rigid PET material, the screw-on structure between the cap and the bottle can be simplified, resulting in improved design and easier manufacturing compared to conventional cap structures.

[0016] The cap of the present invention deforms less when opened and closed, thus reducing the force required, making it easy for the elderly and children to use.

[0017] Figure 1 shows an image illustrating the contact between a sphere and the interior of a cone. Geometrically, the sphere on the inner surface of the cone naturally forms a circular contact area with the cone, which seals the upper and lower spaces inside the cone. Figure 2 shows the relationship between different cone angles and the corresponding diameters of the sphere. The larger the cone angle, the easier it is for the sphere and cone to contact, and the less elastic deformation the sphere undergoes due to the pressure of the tightening force, but conversely, as the cone angle decreases, the more elastic deformation the sphere undergoes due to the pressure, which is greater. Figure 3 is an example of the design of a bottle neck and cap for a PET bottle. In this example, a part of the sphere is provided on the cap, and a part of the inner surface of a cone with an angle of approximately 45° with the axis is provided on the inside of the bottle neck. As shown in the figure, the liquid-contacting part of the cap is spherical. Example 1 is the opposite of Figure 3, with a part of the cone on the cap side and a part of the sphere on the bottle neck. In this example, the bottle neck is part of a sphere, which not only results in a smoother bottle neck, but also allows the cap shape to maintain a design similar to conventional PET bottles, as the conical part is located at the corner of the cap. (Example 2) is an example in which part of the sphere is used as the contact surface on the cap side, but the non-contact surface is flat, making it suitable for containers with large cap sizes, such as wide-mouth bottles. (Example 3)

[0018] By providing a spherical surface and a conical inner surface on the contact surfaces of the cap and the bottle neck, respectively, the geometric contact between the spherical and conical inner surfaces achieves positioning and sealing, thus easily enabling a tight seal between the cap and the bottle. Furthermore, when closing the cap, less deformation of the cap is required compared to conventional methods, and sealing can be achieved with less force and movement of the scroll.

[0019] This method of sealing a container with minimal deformation requirements for the cap can be applied not only to PET bottles but also to the mouths and caps of similar containers such as wide-mouth bottles, glass bottles, and metal cans.

[0020] Figure 3 is a diagram illustrating one embodiment, showing an example of a PET bottle and its cap that seals through contact between a sphere and a cone. The cap is part of the sphere, and the top of the bottle's neck is formed as part of the cone.

[0021] Figure 4 is a diagram illustrating one embodiment, showing an example of a PET bottle and its cap that seals through contact between a spherical and a conical surface. In this example, the cap is part of the cone, and the edge of the bottle's opening is part of the sphere.

[0022] With 480 billion PET bottles consumed annually, this product has had a significant impact on people's production and lives. Even small improvements in the convenience of using PET bottles, slight increases in their productivity, and small advancements in their recycling can have a major positive impact on improving people's lives, protecting the environment, and promoting resource reuse.

[0023] 1. The inner surface or part of a cone 2. The surface or part of a sphere 3. The neck of a bottle 4. The cap

Claims

1. A PET bottle and its cap that utilize the sealing principle of a sphere and the inner surface of a cone, wherein the mouth of the PET bottle or the cap has a portion that comes into contact with each other, and the contact portion is shaped like a sphere and the inner surface of a cone, thereby achieving airtightness inside the PET bottle.

2. The PET bottle and its cap according to the claim, characterized in that the cap according to the claim can be made from the same material as the PET bottle according to the claim.

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