JPS63272605A - Preparation of plastic container - Google Patents

Abstract

PURPOSE:To perform bonding even when a content is adhered to a fused surface, by filling a plastic container having an outwardly opened inclined flange formed to the open part thereof with content and allowing a hermetically sealing plate having an inclined flange to oppose to the open end of the body part of said container to melt and fix both inclined flanges by an ultrasonic wave. CONSTITUTION:A container 1 is formed into such a structure that the upper and lower ends of a body part 2 having a circular cross-section are respectively closed by a top plate and a bottom plate 4 and molded by blow molding. When the protruding part 6 of the container 1 is allowed to pass through a heating ring 8 from the large diameter side thereof, the leading end part of the protruding part 6 is brought into contact with the inner surface of the heating ring 8 to be fused and the body part 2 is opened on the bottom part side thereof and the protruding part 6 is separated into inclined flanges 6a, 6b. The open side of the container 1 is turned upwardly to fill the container with content. The fused bottom plate 4 is allowed to cover and a peripheral jig 9 is engaged and contacted with the inclined flange 6a on the side of the body part 2 and both inclined flanges 6a, 6b are pressed while an ultrasonic wave is applied to said flanges by a tool horn 10. The inclined flange 6b of the bottom plate 4 is reversed to be bonded to the inclined flange 6a of the body part 2 under pressure and both flanges are welded under heating by the ultrasonic wave.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a plastic container, which involves filling a hollow plastic container molded by blow molding with contents and then sealing the lid. .

[Conventional technology]

A conventional method for manufacturing this type of plastic container is disclosed in Japanese Patent Application Laid-Open No. 174352/1983. In this conventional device, a flange is formed in the opening of the main body, and the flange has a planar shape perpendicular to the axis of the main body.
Similarly, the flange of the lid, which is formed in a planar shape perpendicular to the axis, is heat-pressed to melt and seal the lid.

As for the above-mentioned heat-compression bonding means, the opposing surfaces of both flanges are heated with a heating plate and then crimped (heat-sealed), or both flanges are crimped and then heated and melted by high-frequency dielectric heating. .

[Problem that the invention seeks to solve]

In the above-mentioned conventional method for manufacturing plastic containers, in the method of heating the facing surfaces of both flanges and then welding and sealing them,
It is difficult to heat only the sealing surface, and the heating time is also long, and furthermore, if the contents adhere to the sealing surface, there is a problem that it may cause a seal failure. In addition, in the case of high-frequency dielectric heating, only the flange part can be heated, but the plastics that can be heated are essentially limited to those with a large loss coefficient (tan δ) such as polyvinyl chloride and polyamide, and the contents are There is a problem in that when the content adheres to the joint surface, the moisture content is heated, resulting in poor welding.

[Measures 9 and operations for solving the problems] The present invention was made in consideration of the above-mentioned problems, and it is possible to heat only the welding surface, and also to join even if the contents adhere to the welding surface, and furthermore, The purpose of the present invention is to provide a method for manufacturing a plastic container that can be welded with high bonding strength. After filling the container with contents, a sealing plate having an inclined flange is opposed to the open end of the body, and both inclined flanges are connected to a circumferential jig and a tool horn forming an expanded clamping gap. and apply ultrasonic waves to this part, and the both inclined flanges are melted and fixed by the heat generated by the ultrasonic waves.

〔Example〕 Embodiments of the present invention will be described based on the drawings.

In the figure, 1 is a plastic container (hereinafter simply referred to as a container) used in the method of the present invention, and this container 1 has a body 2 having a circular cross section and its upper and lower ends closed with a top plate 3 and a bottom plate 4, respectively. It is shaped and molded by blow molding.

In the upper part of the body part 2, a stepped recess 5 having a depth corresponding to the wall thickness of the body part 2 is formed in a band shape, and in the lower part of the body part 2, a cross-sectional shape is formed into a triangular mountain shape. The convex portion 6 is formed in an annular shape. Further, a handle 7 is integrally formed on the top plate 3 with a thin base and rotatable.

Reference numeral 8 denotes a heating ring having a heating surface on the inside, and the heating surface of the heating ring 8 has a tapered shape ranging from a size larger than the outer diameter of the convex portion 6 of the container 1 to a size slightly smaller.

Reference numeral 9 denotes a circumferential jig having a tapered surface 9a shaped along one side of the convex portion 6 and a cylindrical surface 9b shaped like shaped along the body 2;
10 is a tool horn having a tapered surface 10'a opposite to the tapered surface 9a of this circumferential jig 9, and this tool horn 10 is adapted to be moved in the axial direction with respect to the circumferential jig 9. ing. Further, ultrasonic waves are applied to the tool horn 10, so that the object held between the tapered surface 10a of the tool horn 10 and the tapered surface 9a of the circumferential jig 9 can be ultrasonically heated. .

The method of the present invention using each of the above members will be explained below.

(1) Pass the convex portion 6 of the container 1 inside the heating ring 8 from its large diameter side (FIGS. 1 and 2).

As a result, the tip of the convex part 6 comes into contact with the inner surface of the heating ring 8 and is fused, the bottom side of the body part 2 is opened, and the convex part 6
is separated into inclined flanges 6a, 6b.

(2) Fill the container 1 with the contents from the open side with the open side facing upward.

(3) Cover the open part with the bottom plate 4 cut in step (1) above, and fit and abut the circumferential jig 9 on the inclined flange 6a side of the body 2, and then use the tool horn 10 to connect the inclined flange 6b of the bottom plate 4. Press the circumferential jig 9 and the tapered surface 9a of the tool horn 10.

At 10a, the both inclined flanges 6a and 6b are connected to the tool horn 1.
Press while applying ultrasonic waves to 0 (Figures 3 and 4)
.

As a result, the inclined flange 6b of the bottom plate 4 is inverted and pressed to the inclined flange 6a on the body 2 side, and is heat-welded by ultrasonic waves. At this time, both inclined flanges 6a, 6b
Since the contact area is located in the compression direction of the circumferential tool 9 and the tool horn 10, shear and stress are applied to the contact surface which is heated and melted by ultrasonic heating, thereby firmly performing the melting and crimping.

In the above molding method, the double inclined flange 5a.

The tip of the fusing part 6b is rounded, so if the container 1 is a multilayer container with a barrier layer interposed inside it,
As shown in FIG. 9, the barrier layer 11 is surrounded by the inner and outer layers 12 and 13, which are cut into a circle, and is isolated from the outside air, so that the barrier layer 11, which is susceptible to moisture, can be protected from the outside air.

The inclination angle α of the convex portion 6 is preferably 20 to 70°. If it is less than 20", pinholes will easily occur in this part during blow molding, and if it exceeds 70°, the tool horn 1
This is because the inclined flange 6b on the bottom plate side becomes difficult to reverse when pressed at 0.

Also, the angles of the tapered surfaces 9a and 10a of the circumferential jig 9 and the tool horn 10 are slightly different, and the angles of the tapered surfaces 9a and 10a of the circumferential jig 9 and the tool horn 10 are slightly different.
The shape of the gap formed by a and 10b becomes narrower from the proximal end toward the distal end. Also, both of the above.

It is preferable that the gap formed by 9b at the time of clamping be 30 to 90% of the total thickness of both concave pieces to increase welding strength.

゛When the bottom plate 4 and its inclined flange 6a are reversed and joined to the inclined flange 6a on the body side, the container becomes as shown in FIG. This becomes an inclined flange, and the container 1 can stand on its own in a stable state at this portion.

Note that the cross-sectional shape of the container 1 is not necessarily limited to a circular shape, and may be other than circular, such as a square shape.

In addition, in the above embodiment, after the body and the bottom are integrally molded, they are separated by melting at the top of the convex part, and then the inclined flanges of both are melted and fixed. The slanted flange is attached to the tool horn 2 when melted and fixed.
0, and then face the inclined flange on the opposing body side. However, if the body and the bottom plate are molded separately, the inclined flange on the bottom plate side is turned from the beginning to the inclined flange on the body side. It may also be tilted in the same direction.

When taking out the contents 14 of the container 1 formed as described above, the upper corner of the stepped portion 5 is cut into an annular shape using a force/tweak 15, as shown in FIG.

After that, as shown in Figure 8, fit the cut portions and
Use the side as a lid.

The material constituting the container 1 used in the present invention is not particularly limited as long as it is a thermoplastic, but in the case of a multilayer container, the inner and outer layers are made of a hydrophobic resin such as polyethylene or propylene, and the middle layer is made of an oxygen barrier. Barrier resins with high properties, such as saponified ethylene-vinyl acetate copolymers,
Polyamide, vinylzoline chloride, polyvinyl alcohol, etc. are used. Further, adhesive resin such as modified polyolefin may be interposed on both sides of the intermediate layer. Alternatively, a barrier resin layer mixed with a hydrophilic substance such as a super absorbent polymer or a desiccant agent may also be used.

Note that the sealing plate in the present invention refers to a member that melts and fixes the open end, and is not limited to the bottom plate in the narrow sense, and for example, the top plate in the embodiments is also included in the sealing plate.

〔Effect of the invention〕

According to the present invention, only the welding surface can be heated, and even if contents adhere to the welding surface, welding can be performed, and welding can be performed with extremely high bonding strength.

[Brief explanation of drawings]

Figures 1 to 4 are cross-sectional views of essential parts showing the steps of the method of the present invention, Figure 5 is a front view of a blow-molded plastic container, and Figure 6 is a plastic container filled with contents and welded to the bottom plate. FIG. 7 is a partially sectional front view of the container, FIG. 7 is a sectional view showing the opening operation, FIG. 8 is a partially sectional view showing the temporary lid state, and FIG. 9 is a sectional view showing the fusing part in the multilayer container. 1 is a plastic container, 2 is a body, 3 is a top plate, 4 is a bottom plate,
5 is a stepped recessed portion, 6 is a convex portion, 5a and 8b are inclined flanges,
8 is a heating ring, 9 is a circumferential jig, and 10 is a tool horn.

Claims (1)

[Claims] A plastic container 1 in which one end of the body 2 is open and an inclined flange 6a which is inclined in a widening shape is formed in this open part.
After that, a sealing plate having an inclined flange 6b is opposed to the open end of the body 2, and both inclined flanges 6a and 6b are connected to a circumferential jig 9 and a tool horn 10.
A method for manufacturing a plastic container, characterized in that the two inclined flanges 6a and 6b are melted and fixed by the heat generated by the ultrasonic waves by applying ultrasonic waves to these parts.