JPS5854021B2 - Method for manufacturing thermoplastic containers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a thermoplastic container, and more particularly to a method of manufacturing a soft thermoplastic container, which has a deep container body and has a folded edge at the opening edge. It is something.

BACKGROUND OF THE INVENTION Conventionally, it has been known that blow molding is the most preferable method for molding deep containers from soft thermoplastic materials such as polyethylene.

This is because the vacuum forming method (also known as pressure forming method), in which a plastic sheet that has been heated and softened is stretched and formed using air pressure, is not suitable for deep drawing. This is because the injection molding method requires complex and expensive molds, and the molding process requires complicated manipulation of each part of the mold, resulting in extremely low productivity.

However, blow molding is not suitable for objects with complex shapes.
It is believed that this type of folded edge formation is not possible.

That is, in the blow molding method, the mold is opened in half to take out the product, so if there is a folded edge, the folded edge will get caught in the die.

Therefore, the present invention attempts to manufacture a plastic container with a deep folded edge using a blow molding method by completing the folding process by secondary processing after blow molding, such as forming the folded edge. It is something.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the accompanying drawings.

Fig. 1 shows a container manufactured by the method of the present invention containing frozen confectionery M, which is made of a soft thermoplastic material such as polyethylene or foamed polyethylene, and is made of a deep cylindrical container body 1 with an opening. After storing a frozen dessert M such as ice cream or sherbet in the container body 1, a lid 3 having a thermoplastic plastic layer 3a on the lower surface is placed on the folded edge 2. It is made by hot-bonding.

When consuming this frozen dessert container, remove the lid 3 and squeeze the container body 1, and the frozen dessert M will be pushed out from the opening. It's something you put into your mouth.

This container is made of a soft thermoplastic material, and the lower part of the container body 1 has a gradually smaller diameter, so that when the container body 1 is gripped, the frozen confectionery M is easily pushed out.

Furthermore, the folded edge 2 of the container is used to heat-bond the lid 3 and to prevent the texture from being affected even if the lip comes into contact with the opening when the frozen dessert M is eaten directly from the container. be.

In the first step of manufacturing a container having the above shape, a hollow body 1a having a shape as shown in FIG. 2 is formed by blow molding a thermoplastic material by conventionally known blow molding means.

This hollow body 1a is formed by connecting a large diameter part 12 to the upper part of a container main body part 1 via a step part 11.

Normally, this blow molding involves placing a heated and molten plastic material called a parison, which has been preformed into a tube shape, between molds, blowing air into the parison, making it fluff, and then cooling and solidifying it. However, in the conventional method, the step part 1
1 and a large diameter part 12 are not provided, and the upper part of the container body part 1 is called a neck part and is cut off later.

In the second step, the large diameter portion 12 of the hollow body 1a formed as described above is cut at the horizontal plane 10 located above the step portion 11, and the large diameter portion 12 of the hollow body 1a formed as described above is cut at the horizontal plane 10 at a position above the step portion 11. The large diameter portion 12a of a predetermined height is formed in series.

The third step is to remove the large diameter portion 12a that is connected to the container body 1 side.
is folded back to the outside of the container main body 1 at the stepped portion 11,
This stepped portion 11 and the folded large diameter portion 12a form a folded edge 2 as shown in FIG.

In order to store and seal the frozen confectionery M in the container thus formed, as shown in FIG. A ring 4a is fitted into the lower part of the portion 2 to hold it, and after storing the frozen dessert M, the lid 3 is folded back and placed on the edge 2, and the lid 3 is thermally bonded by pressing the heater 5 from above. It is.

Since the manufacturing method of the present invention is as described above, the container body 1 is deep and has a folded edge by using a blow bottom shape suitable for forming a deep container and a simple secondary process of cutting and folding the large diameter portion 12. The container having the section 2 can be easily manufactured.

Among these, blow molding is known to have various advantages compared to other molding methods, such as a simple and low-cost mold, high productivity, and the ability to use plastic materials that are easily thermally decomposed. Even if the process of cutting and folding the large diameter portion 12 is added, it is more economical than other molding methods.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of a frozen confectionery housed in a container manufactured by the method of the present invention, Fig. 2 is a longitudinal cross-sectional view of a hollow body formed during the manufacturing method of the present invention, and Fig. 3 is a longitudinal cross-sectional view of a container manufactured by the method of the present invention. FIG. 4 is a longitudinal cross-sectional view of a container manufactured by the method, and FIG. 4 is a cross-sectional view showing an example of a method for storing frozen confections in the container and sealing the lid. 1... Container body, 2... Folded edge, 3...
Lid, 3a...Thermoplastic plastic layer, 10...Horizontal surface, 11...Step part, 12.12a...Large diameter part, M
···Frozen dessert.

Claims (1)

[Claims] 1. In the first step, a step 11 is formed on the upper part of the container body 1 using a thermoplastic soft plastic material by blow molding means.
In a second step, the large diameter portion 12 of the hollow body 1a is cut at the horizontal surface 10 of the upper part of the stepped portion 11, and the In the third step, the large diameter portion 12a that remains continuous to the container body 1 side by cutting the large diameter portion 12 is cut back to the outside of the container body 1 at the stepped portion 11 to form the container body. 1. A method for manufacturing a thermoplastic plastic container, characterized in that a folded edge 2 is formed at the opening of the container 1 by the stepped part 11 and the folded large diameter part 12a.