JPS6160459A - Vessel plug and manufacture thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a container stopper with excellent sealing performance and a method for manufacturing the same.

Traditionally, natural cork liners and polyvinyl chloride liners have been used for liners for container closures such as crowns and caps, but since cork liners made from natural cork are natural products, they are in short supply and costs are rising due to increased demand. become. Furthermore, cork turns black due to the formation of iron tannins due to iron. Also, depending on the type of contents, there were drawbacks such as adhesion to the mouth of the bottle.

In recent years, vinyl plastisol liners have replaced cork (
A liner made of polyvinyl chloride) has appeared, but this
The spin lining method involves supplying Jfi vinyl plastisol into the crown, spreading it into the container stopper using centrifugal force, and then heating and melting the resin in a heating opener. A molding method is used in which the material is molded using a punch heated to .degree. C. and then heated and melted in an open chamber. However, both of these methods provide cold material and heat the material within the container stopper to obtain sufficient thickness for sealing performance, but require large equipment for foaming. Furthermore, container stoppers are heated at high temperatures for long periods of time, which can damage the printed surface and cause thermal deterioration, and alcohol must be used as plasticizers must be used extensively.

There were drawbacks such as the plasticizer being extracted and transferred, causing a change in taste and odor.

As mentioned above, a container stopper with a polyethylene resin liner was completed in order to solve the drawbacks of the container stopper liner currently in typical use. There are two methods: one method is to firmly seal the container, and the other is to form a liner inside the container cap using a molding bunch which is heated and cooled while simultaneously supplying molten polyethylene resin into the container cap.

The former method provides a liner with good sealing performance, but it cannot be mass-produced, is expensive, and has drawbacks such as reduced work efficiency due to the liner falling off during capping.

The latter also shows good sealing properties for new bottles;
There is a drawback that the sealing performance is reduced due to variations in the dimensions of the bottle mouth and scratches. In addition, due to the hardness of polyethylene, which is a disadvantage of polyethylene, when using a normal seal type, the top of the container stopper swells due to repulsive force when the stopper is plugged, resulting in a doming phenomenon.
There were drawbacks such as reduced sealing performance and gas leakage.

The present invention eliminates these drawbacks and provides an ideal container stopper with improved sealing performance after capping, and a method for manufacturing the same. This container stopper is characterized by being provided on the inner surface of the container stopper, such as a cap.

Examples of the water-absorbing resin include starch-based resins, cellulose-based resins, and synthetic polymers such as polyacrylic acid-based resins, Popal-based resins, and polyoxyethylene-based resins, and any of these may be selected. Acrylic acid resin is preferable in consideration of physical properties, expansion rate, etc. The amount added to the synthetic resin is about 5 to 50 parts, but preferably 1
It is preferable to use it in a range of 0 to 20 parts. This is because if the amount added is too small, the degree of foaming will be low and sealing properties cannot be achieved, and if it is too large, water will be absorbed too much, which will cause problems in terms of strength, which will also reduce the sealing properties.

In addition, synthetic resins with low hardness, i.e., soft resins, are suitable in order to facilitate expansion by water-absorbing resins, and considering that they are used for food, vinyl chloride paste, polyethylene, polyethylene-acetic acid paste, etc. Vinyl polymer resins, ethylene, propylene-based elastomers, and other generally called thermoplastic elastomers are good, but polyethylene-based resins are particularly advantageous in terms of water absorption, and polyethylene-vinyl acetate copolymers are most suitable. be.

As a method for obtaining this container stopper, a synthetic resin containing the water-absorbing resin is applied to the inner surface of the container stopper of a metal plate such as a steel plate or an aluminum plate, and then the metal plate is applied to a container stopper such as a crown or cap. By punching and molding, a desired container stopper can be obtained.

When punching and molding into container stoppers like this, the thickness of the synthetic resin layer is preferably in the order of 0.15 to 0.25 from the viewpoint of workability, etc. On the other hand, in order to maintain the sealing performance of the bottle mouth, the thickness of the synthetic resin layer is preferably 0.4 nm or more. It is. The present invention satisfies this requirement, and the synthetic wreath containing a water-absorbing resin expands in volume when it absorbs water, but 1.
It is made to tighten 5 to 6 times to create a sealing performance. For example, the synthetic resin layer is coated to a thickness of Q, 2 ml/g, and the container is capped to allow the synthetic resin layer to absorb water. It is expanded to at least 0.4 to 0.5 degrees to obtain sealing properties.

In order to make the synthetic resin layer absorb water quickly after the container stopper is plugged into the mouth of the bottle, it is desirable that the water-absorbing resin be arranged on the surface as much as possible. By adding an aliphatic solvent to the formulation to form an organosol, more effective sealing properties can be obtained.

Further, the hardness of the synthetic resin layer is preferably less than 70 on the X-S hardness tester A, and optimally about 60. This is because high hardness delays water absorption. However, this is also necessary depending on the application and is not particularly limited.

Further, the synthetic resin layer does not need to be provided over the entire surface, and may be applied in a ring shape along the mouth of the bottle.

Next, examples will be shown.

Vinyl chloride paste resin 100 parts plasticizer (
DOP) 70 parts Stabilizer (calcium stearate) 2 parts Water-absorbing resin (acrylic acid resin) 10 parts Apply the paste of the above composition to a steel plate coated with adhesive using a roll coater to a thickness of 0.2 mm. It is applied uniformly and heated in an open setting at 170° C. for 10 minutes to gel.

The obtained steel plate coated with the synthetic resin layer is punched and formed into a desired container stopper using a conventional Crown Seiko press or a cap molding press. When the container stopper obtained in this way is plugged into the mouth of a bottle filled with the contents, the synthetic resin layer will be 1.5 to 1.5 mm thick in the thickness direction.
It expanded six times and exhibited excellent sealing performance. Both new and damaged bottle caps were prepared and capped with container stoppers, and in both cases, no leakage of contents was observed and excellent sealing performance was achieved. This is especially true for damaged bottle openings, because unlike other seal liners, the seal expands and fills the damaged area after capping. It exhibits excellent sealing performance. In addition, it can always withstand external shocks and deformations such as vibrations and drops after capping, and maintains excellent sealing performance.

In addition, a synthetic resin of polyethylene-vinyl acetate copolymer is also made to contain a water-absorbing resin, extruded into a thin film using an extruder, pressed onto a steel plate coated with adhesive, and heated to apply a synthetic resin layer. When the sample was punched and molded into a desired container stopper using a press and this was plugged into the mouth of a bottle, it exhibited the same excellent sealing performance.

In this way, the present invention is completely different from the conventional method of sealing by pressing the liner with plugging pressure using an elastic seal liner, and after plugging, the sealed portion absorbs moisture and expands, completely sealing the gap. Therefore, it is possible to obtain an ideal container stopper that exhibits excellent sealing performance even for damaged bottle openings, where there was a risk of leakage in the past, and that also exhibits excellent sealing performance especially for bottle openings that are subject to internal pressure. .

Claims (8)

[Claims] (1) A container stopper, such as a crown or cap, characterized by having a synthetic resin layer containing a water-absorbing resin on the inner surface of the container stopper. (2) The container stopper according to claim 1, wherein the synthetic resin containing the water-absorbing resin is vinyl chloride paste. (3) Claim 1 in which the synthetic resin containing the water-absorbing resin is a thermoplastic elastomer or a polyethylene resin.
Container stopper as described in section. (4) Synthetic resin containing water-absorbing resin is polyethylene.
The container stopper according to claim 1 or 3, which is a vinyl acetate copolymer. (5) Manufacture of a container stopper characterized by applying a synthetic resin containing a water-absorbing resin to the inner surface of a metal plate and punching and molding the metal plate into a container stopper such as a crown or cap. Method. (6) The method for producing a container stopper according to claim 5, wherein the synthetic resin containing the water-absorbing resin is vinyl chloride paste. (7) Claim 5, wherein the synthetic resin containing the water-absorbing resin is a thermoplastic elastomer or a polyethylene resin.
The method for producing a container stopper as described in Section 1. (8) Synthetic resin containing water-absorbing resin is polyethylene.
The method for producing a container stopper according to claim 5 or 7, wherein the container stopper is a vinyl acetate copolymer.