JPS58194532A - Method of fixing end plate in paper can - 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 method for fixing end plates in paper cans, the purpose of which is to fix synthetic resin end plates to the paper can body with sufficient airtightness.

Conventionally, as a method for fixing end plates made of synthetic resin to paper can bodies, a method is known in which an end plate formed into a cap shape is fitted onto the can body using the elasticity of synthetic resin. In this method, the end plate and the wall surface of the can body are only brought into contact with each other and are not fixed to each other, so it is difficult to obtain sufficient airtightness, and the reliability of airtightness is also low.

However, this invention attaches upper and lower molds for molding end plates to the end of a paper can body, then injects heat-plasticized synthetic resin between the upper and lower molds to mold the end plates, and molds the end plates. Since the peripheral portion and the paper can body are fixed, it is possible to easily and reliably fix the end plate to the paper can body with high airtightness, and the above-mentioned conventional problem 11- is solved.

The following invention will be explained based on the embodiment shown in FIGS. 1 to 4.

At the end of the paper can body/
are mounted facing each other across the gap between the end plates to be formed. The upper die λ is provided with an annular groove S into which the edge of the paper can body is loosely fitted, and the edge of the paper can body is loosely fitted into the annular groove S to be mounted.

On the other hand, the lower mold 3 is a disk having a diameter approximately equal to the inner diameter of the paper can body, and is inserted and attached from below (in the figure) to the paper can body.

B in the figure is a split-shaped side plate, which is used to close the lower end of the gap formed on the outer wall side of the paper can body.

After attaching the upper and lower molds 3 to the paper can body as described above,
A synthetic resin (for example, polypropylene, polyethylene, polyester) plasticized by heating is injected from the nozzle 7 of the upper mold unit into the gap t at a predetermined pressure (appropriately determined depending on the shape and size). The injected synthetic resin is between 1/J
a, and by cooling and solidifying, an end plate g is formed, and the contact surface between the end plate g and the paper can body is fixed. After that, attach the upper and lower molds A, 3 and the side plate A to the arrows 9.10 in Fig. 3, respectively.
Move backward like ゜//. In the figure, 72 is a rib.

Next, Figure S shows a paper can body with a curled part /3 on the outside of the end.
The end plate g is fixed by the method of this invention, No. 6
The figure shows an end plate g fixed by the method of the present invention to a paper can body l having a curled part /3 on the inner side of the end. As shown in Figures S and 6 above, the curled part/
3, it is possible to embed the curled portion /3 with the mouth-forming resin, and the fixing strength and airtightness of the end plate can be further improved. Further, in the example shown in FIG. 4, the end plate G can be formed using only the upper and lower molds, and the side plate B is not required.

Next, FIG. 7 shows an end plate g formed using upper and lower molds having curved opposing surfaces. In each of the above embodiments,
By using an upper mold having an annular groove S and covering the edge or curled portion of the paper can body with synthetic resin, the adhesion strength and airtightness of the end plate can be improved. It is only necessary to secure the end plate g and the paper can body to obtain the desired strength and airtightness, and it is not necessarily necessary to cover the edge or curled portion of the paper can body with a synthetic resin. Not necessary. ′! If a synthetic resin layer is provided on the outside, inside, or inside and outside of the paper can body, the adhesion strength and airtightness between the end plate and the paper can body will be further improved.

That is, according to this invention, at the end of the paper can body,
, l Attach upper and lower molds for molding end plates, then inject heat-plasticized synthetic resin between the upper and lower molds to mold the end plate, and fix the peripheral edge of the end plate to the paper can body. Therefore, the end plate can be easily and reliably fixed to the paper can body with high airtightness and strength.

[Brief explanation of drawings]

Figure 1 is a plan view of a can with end plates fixed by the method of the present invention, Figure 2 is a partially cutaway front view, and Figure 3 is a partial view of a paper can with upper and lower molds attached. FIG. 2 is a partially enlarged sectional view of FIG. 2, and FIGS. 5 to 7 are partially enlarged sectional views showing other examples of cans with fixed end plates according to the present invention. be. / Paper can body Co. Upper mold 3. Lower mold agent Shoji Suzuki

Claims (1)

[Scope of Claims] / Upper and lower molds for molding end plates are attached to the end of the paper can body, and then heated and melted synthetic resin is injected between the upper and lower molds to mold the end plate, and the end plate is molded. A method for fixing end plates in a paper can, characterized in that the peripheral edge of the plate and the paper can body are fixed. The upper and lower molds are arranged opposite to each other through a gap in the end plate to be formed, and a part of the gap is A method for fixing an end plate in a paper can according to claim 1, wherein the paper can is attached with the edge of the paper can body facing toward the end plate.