JPS5927383Y2 - bag - Google Patents

Description

[Detailed description of the invention] This invention is based on low density polyethylene, high density polyethylene,
Bags made of films and composite films made of single or blended thermoplastic resins such as polypropylene and ethylene-vinyl acetate copolymer, at the creases on both sides of the bag or at the melt-cut seal part near the opening of the bag. The present invention relates to a bag characterized by having a notch in a direction perpendicular to the folded portion or the melt-cut seal portion.

Methods for manufacturing bags made of thermoplastic resin include a method in which one side end of a cylindrical film formed from a tubular die is heat-sealed, a film in which the cylindrical film is cut open, and
There are bags and the like that are made by continuously folding a flat film produced from a T-shaped die in half in the longitudinal direction and fusing it in a direction perpendicular to the flow direction.

A bag made in advance in this way is called a preform bag.

The filling of articles into preformed bags can be done manually or mechanically and automatically.

Packaging of bread, sweets, etc. is also carried out automatically using preformed bags.

By the way, in the automatic packaging process, when opening a preform bag, it is first opened using compressed air, then opened wider using iron claws, and then the contents are inserted. For bags and the like that are easily torn due to the thermal conditions in which the film or the fusing seal part is easily torn, there are many accidents in which the creases on both sides are torn from the opening part during the above-mentioned opening process.

Most of the tearing occurs from the folding part or the opening of the fusing part.

Countermeasures have been taken to prevent such accidents, such as increasing the size of the bag or modifying the material of the bag to be softer, but these methods are not always satisfactory from a cost and technical perspective. It wasn't.

The present invention makes it extremely easy to solve these accidents.

That is, on both sides of a bag made of thermoplastic resin, notches 3 are formed at a location near the opening 2 of the fold line 1 or the melt-cut seal part 1 in a direction perpendicular to the fold line or the melt-cut seal part 1 during or after bag making. By inserting it into one or more places, the stress received when the mouth is opened by compressed air and the mouth by nails causes tearing at the end, but the stress propagation stops at the notch, and the stress at the notch stops. Since the bag is split into two in the horizontal direction, the bag can only be broken at the top of the bag.

The shape of the notch may be a cut made by a knife blade or a ■-shaped cut.

The bag according to the present invention is particularly effective for twist bags whose openings are squeezed after filling and tied with tape or the like, and there is no problem in appearance even if some tear propagation occurs.

Therefore, the present invention can very easily prevent bag breakage accidents, which were particularly common at the mouth openings of conventional automatic packaging machines.

[Brief explanation of the drawing]

Fig. 1 is a front view of a bag showing an embodiment of the present invention, and Fig. 2 is a side view of the same.
2 indicates an opening, and 3 indicates a notch.

Claims (1)

[Scope of utility model registration request] 1. A bag made of a thermoplastic resin, wherein a notch is made in a direction perpendicular to the folded portion or the melted seal at a location close to the opening of the bag at the folded portion or the melted seal on both sides.