Asahi Chemical Polyflex Ltd.

Kiyoshi Nakashima

Hisao Kai

A laminate film for forming a tightly sealed bag that can be opened easily by tearing at an edge thereof. The film is a laminate of a substrate layer and a heat seal layer, the substrate layer having a multiplicity of through cuts formed therein, said through cuts being partially or wholly filled by the heat seal layer material.

Laminated film for forming an easily openable tightly sealed bag

A process for producing a tightly sealed bag that can be easily opened by tearing at an edge thereof. According to the process a multiplicity of through cuts are formed along a line in a laminate film having at least one substrate layer and at least one heat seal layer. The laminate film is formed into an open bag with the line of through cuts provided along an edge to be sealed of the bag and edges of the open bag are heat sealed to form a sealed bag. In an alternative embodiment of the process, a multiplicity of through cuts are formed along a line in a substrate film and a heat seal film is laminated to the substrate film provided with the through cuts to form a laminate film prior to forming the sealed bag.

Method for producing an easily openable tightly sealed bag

A device for forming slits, or through cuts, in a plastic film. The device is a disc having a circumferential surface and pseudotriangular slender cutting edges consisting of protrusions aligned linearly in a plurality of straight rows extending around the entire circumferential surface, the protrusions extending outwardly from said circumferential surface at angle of at least 60.degree. and no greater than 100.degree..

Slit imparting device for forming through cuts in a plastic film

This invention provides an easily openable tightly sealed plastic bag which is formed of a film containing at least a substrate layer and a heat seal layer and is possessed of a sealed part whose substrate layer contains a multiplicity of through cuts, these cuts being formed substantially on the edge lines and partly or wholly closed with the heat seal layer. This tightly sealed bag safely retains the practical strength normally expected of any bag and avoids accidentally sustaining rupture while the bag is being transported or handled and yet permits itself to be opened with the force of finger tips. This invention manifests its utility particularly in a tightly sealed bag which is formed of a substrate of high strength and high barrier property. This invention further provides a method suitable for the production of the tightly sealed bag described above and a device to be used in working the method. The easily openable tightly sealed plastic bag of particularly desirable quality can be obtained by the method and the device so provided by this invention.

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Ageo, Japan

Kiyoshi Nakashima