JPS593140B2 - Method for manufacturing mesh packaging material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mesh packaging material and a method for manufacturing the same.

More specifically, it is a packaging material made of a cylindrical mesh made of foamed plastic with high extensibility in the circumferential direction, and the foamed wires are formed between diagonally intersecting inner and outer foamed wires of the cylindrical mesh and in the circumferential direction of the cylindrical mesh. A net-like packaging material having a cohesive band integrally fused with a strip at or near one end, and a net-like package formed by folding the center part of the cohesive band having net-like parts on both sides as an end. A cylindrical network made of foamed plastic with high elasticity in the circumferential direction is extruded from a plurality of extrusion grooves provided on the sliding surfaces of the outer die and inner die, which slide and rotate in opposite directions. In the manufacturing method, one or both of the outer die and the inner die are periodically reciprocated in the direction of the center axis of the extruder, and an annular resin passage is periodically formed between the outer die and the inner die 10. A cylindrical net having a fusion zone periodically formed between diagonally intersecting inner and outer foamed filaments of the cylindrical net and integrally fused with the foamed filaments in the circumferential direction of the cylindrical net. This invention relates to a method for manufacturing a net-like packaging material, which comprises extruding a cylindrical net having the cohesive zone and continuously cutting the cohesive zone so that the cohesive zone is at or near one end.

The manufacturing method for plastic cylindrical nets is published in Japanese Patent Publication No. 34-4185.
Various methods have been proposed, including the method disclosed in the above issue, but basically, foamable molten resin is extracted from a plurality of extrusion grooves drilled on the sliding surfaces of inner and outer dies that rotate in opposite directions 20. This is a method to obtain a cylindrical mesh by extruding.

Furthermore, various net-like packaging materials have been disclosed in which this cylindrical net is cut to an appropriate length and the ends are treated to be used as packaging materials for fruits and the like. Example 25 For example, in Utility Model Publication No. 41-2155 and Utility Model Publication No. 42-2858, the idea of bending and welding each filament at the end of a cylindrical mesh to the inside of the tube is described in Utility Model Publication No. 49-409.
For No. 99, a label is attached to the circumferential part where one end of the cylindrical mesh is gathered together so that the periphery overlaps, and the contents such as fruits are removed.
Packaging material that prevents 0-digits from falling was published in 1973.
No. 86 has a mesh part that is finer than the other parts near one end of the mesh packaging, and the fine mesh part is brought into close contact with the lower side of the contents such as fruit to prevent the contents from falling out even slightly. The 35 packaging materials that were intended were also
No. 1256 proposes a packaging material in which adjacent foamed filaments are brought together with an opening at one end and adhered to each other to prevent contents such as fruit from falling out. What is understood from the above prior art is that there is a demand in the market for packaging materials that do not allow the contents of fruits and the like to fall out.

However, in order to satisfy the above market demands for individual mesh packaging materials, the continuously extruded cylindrical mesh must be cut.
Each net-like packaging material had to be subjected to a secondary process called edge treatment, such as heat-sealing one end or tying it together with string, etc., and the production method had the drawback of extremely low productivity.

As a result of various studies in order to omit the above-mentioned secondary processing step, the present inventor has determined that one or both of the outer die and the inner die of a known cylindrical mesh manufacturing device should be periodically reciprocated in the direction of the center axis of the extruder. By doing so, a fused band integrally fused with the foamed filaments appears between the inner and outer foamed filaments of the continuously extruded cylindrical net and in the circumferential direction of the cylindrical net, We have invented a manufacturing method that can produce mesh packaging materials that meet the market requirements by simply cutting this cylindrical mesh automatically, and have succeeded in omitting the secondary processing step. Next, the manufacturing method of the present invention will be explained based on the illustrated embodiments. FIG. 1 is a longitudinal sectional view schematically showing a manufacturing apparatus used in the present invention.

The outer die 1 is rotated by a clutch 3 rotated by a drive device 10 via a clutch pawl 9, and the inner die 2 is slid and rotated within the outer die 1 by a drive device 11 in a direction opposite to that of the outer die 1. A plurality of extrusion grooves 13 and 14 are formed in the sliding surfaces of the outer die 1 and the inner die 2, respectively, and the extruder A resin reservoir C communicating with 12 is provided. Further, an outer die moving lever 4 is fitted onto the outer periphery of the outer die 1 via a bearing 6. One end of the outer die moving lever 4 is connected to the moving mechanism 5 with a pin 8a, and the other end is connected to the moving mechanism 5 with a pin 8a. 8b
is connected to the fixed arm 7. First, the molten resin extruded from the extruder 12 passes through the channel B, is supplied to the reservoir C, and is extruded from the extrusion grooves 13 and 14, but the outer die 1 and the inner die 2 rotate in opposite directions. As a result, as the extrusion grooves 13 and 14 match as shown in FIG. 2 as they rotate, a cylindrical network in which obliquely intersecting foamed filaments are fused and integrated at their intersection points is continuously produced. It is well known that

While this molten resin is being extruded from the extrusion grooves 13 and 14, the moving mechanism 5 moves the pin 8a side of the lever 4 toward the arrow A
When the outer die 1 is periodically reciprocated in the direction of A resin passage E is formed.

The molten resin is extruded from this periodically formed annular resin passageway E, and the extrusion groove 13 and the extrusion groove 14 as shown in FIG.
A cylindrical network having periodic cohesive zones 18 between the foamed filaments 16 and 17 extruded from each other is continuously produced. By simply cutting the thus produced cylindrical net so that the cohesive zone 18 is located at or near one end, a net-like packaging material having a cohesive zone that prevents the contents from falling out can be obtained. be. Furthermore, a more effective net-like packaging material can be obtained by placing net-like parts on both sides of the cohesive band 18, cutting it, and folding back the cohesive band 18 with the central part as the end. It is optimal for the resin passage to be completely annular, but it is not necessarily limited to this.
For example, the passage may be annular but partially closed.

The width of the cohesive band 18 formed in the circumferential direction of the cylindrical mesh is determined by the time during which the annular resin passage E is formed, that is, the time during which the outer die 1 approaches the extruder 12 side. Therefore, the width of the cohesive zone can be adjusted by controlling the operating time of the moving mechanism 5. Further, by adjusting the thickness of the cohesive zone by controlling the stroke of the moving mechanism 5, the strength of the cohesive zone that is necessary and sufficient to inhibit the circumferential extensibility of the cylindrical mesh can be obtained.

The direction in which the extrusion grooves 13 and 14 are dug is best to be grooved outward from the reservoir C as shown in FIGS. 3 and 4. The trench may be dug parallel to the axis.

However, in this case, the stroke of the moving mechanism becomes large, which increases the size of the device, and if the stroke is to be made small, it becomes necessary to move both the inner and outer dies, making the device more complicated. Furthermore, when cutting the cylindrical mesh, by interlocking the rotational speed of the cutter (not shown) and the mechanism for moving the outer die, the cylindrical mesh that is continuously extruded is periodically exposed. The cohesive zone can be automatically cut by positioning it at or near one end, or by positioning it so that it has net-like parts on both sides of the cohesive zone.

Further, there are various mechanisms for moving the outer dice, such as mechanical/electrical mechanisms, mechanisms using pneumatic pressure and oil pressure, etc., and these may be used as appropriate. The effect of the present invention is that manufacturing capacity can be greatly increased by omitting the secondary processing process of so-called edge processing, which could only be carried out by hand in the past, and it not only reduces costs. The economic advantages of mass production are immeasurable.

[Brief explanation of the drawings] Fig. 1 is a longitudinal cross-sectional view showing an outline of the tubular mesh manufacturing device;
The figure is an enlarged cross-sectional view of the die part, FIG. 3 is an enlarged vertical cross-sectional partial view of the die showing how the extrusion groove is dug, FIG. 4 is an enlarged vertical cross-sectional partial view showing how the annular resin passage is formed, and FIG. The figure is an enlarged cross-sectional view showing the state of formation of the cohesive zone, and FIG. 6 is a schematic diagram showing the state in which the cohesive zone appears periodically on the cylindrical mesh.

Claims (1)

[Claims] 1. Method for manufacturing a cylindrical mesh made of foamed plastic with high extensibility in the circumferential direction, which is extruded from a plurality of extrusion grooves drilled in the sliding surfaces of an outer die and an inner die that slide and rotate in opposite directions. one or both of the outer die and the inner die are periodically reciprocated in the direction of the center axis of the extruder, and an annular resin passage is periodically formed between the outer die and the inner die, Extruding a cylindrical net having periodically fused zones integrally fused with the foamed strands in the circumferential direction of the cylindrical net between the diagonally intersecting inner and outer foamed strands of the cylindrical net; 1. A method for producing a net-like packaging material, which comprises continuously cutting a cylindrical net having a cohesive zone so that the cohesive zone is at or near one end.