TIGHTLY SEALED PAPER CONTAINER PROVIDED WITH OPENING DEVICE

Abstract: A tightly sealed paper container, wherein a through hole (2) is formed in a container material laminated with a thermoplastic synthetic resin layer provided at the outermost layers of the front and rear of a paper board base, a lining member (3) made of synthetic resin and having a smaller hole (4) than the through hole is so positioned that the small through hole of the lining member is included within the through hole of the container material so as to be contacted with the inner surface of the container, and a pull tab piece (5) covering the through hole of the container material is contacted with the outer surface of the container. The surrounding of the small through hole of the lining member slightly projects outwardly from the front surface of the container material. A half-cut line (6) is provided on the outer surface of the container along a boundary between a contact portion of the pull tab piece to the outer surface of the container and a non-contact portion of the pull tab piece for a knob.

Description: This invention relates to a tightly sealed paper container provided with simplified opening device. In general, as an opening device to be secured to a tightly sealed paper container, there has been used a plastic product comprising: a main body of pour-out device including a pour-out tube and a flange portion; and a cap secured to the forward end of the pour-out tube. As methods of attaching the plastic product to an opening portion provided at a predetermined position of the paper container include an internally attaching method of attaching the flange portion to the inner wall surface of the paper container and an externally attaching method of the outer wall surface thereof. Except for these, there has been known one in which a pull tab piece made of an aluminum foil is attached to the opening portion from the outer surface. Out of the above, the pour-out device formed of the plastic product is complicated in its form, whereby, at the time of sterilization prior to the fill-up of a content, there is a possibility that the pour-out device cannot fully be exposed to a hydrogen peroxide gas or the hydrogen peroxide gas remains in the pour-out device. Furthermore, the one, to which the pull tab piece is attached, a cross section of the opening portion tends to be brought into an unstable state due to torn-down laminated resin, so that pour-out operation becomes inconvenient. FR-A-1,309,703 describes a container having the features of the preamble of Claim 1. The present invention relates to a paper container attached thereto with the opening portion, eliminating the above-described disadvantages. The invention provides a tightly sealed paper container according to Claim 1. According to a preferred embodiment of the invention a half-cut line may be provided on the outer surface of the container along a boundary between a contact portion of the pull tab piece to the outer surface of the container and a non-contact portion of the pull tab piece for a knob. According to this invention, the lining member is attached to the inner wall surface of the container, the lining member is partially exposed through the through hole of the container material, and this exposed portion is covered by the pull tab piece. When the pull tab piece is rolled up, contact portions between the pull tab piece, the container material and the lining member are easily peeled off from one another to expose the through hole of the container material, and further, the lining member and the small through hole appear in the through hole. The content is poured out in a sizable flow through a pour-out hole, using the small through hole provided in the lining member. On the other hand, the opening device of this invention is formed of one molded product, and the form thereof is a simplified one having no pour-out tube portion, so that there is no possibility that a portion not exposed to the hydrogen peroxide gas remains at the time of sterilization by the hydrogen peroxide gas or the hydrogen peroxide gas remains in the opening device. The surrounding of the through hole of the lining member slightly project from the front surface of the container material, so that the works of attaching and peeling-off of the pull tab piece can be facilitated. When the aforsaid knob is provided and the knob of the pull tab piece is pulled up at the time of opening, the paper container material is peeled off in layers from the boundary of the half-cut line and one of the peeled-off paper layers is attached to the pull tab piece, so that a trace of opening remains in the container reliably and the safety of the content can be secured. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view showing the process of opening of the pull tab piece of the paper container according to an embodiment of the present invention; and Fig. 2 is a sectional view showing the essential portion of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the drawings showing an embodiment illustrated hereunder. Fig. 1 shows the process in which the pull tab piece is being peeled off in the tightly sealed paper container provided with the opening device according to the present invention. A roof panel of a main body of a paper container 1 is formed with a through hole 2, and a lining member 3 is attached to the through hole 2 from the inner surface of the container, so that a small through hole 4 can serve as an opening portion of a tightly sealed paper container. Further, a pull tab piece 5 is attached so as to cover a portion exposed to the outer surface of the lining member 3 and a portion thereabout. According to the present invention, the material of the main body of paper container 1 is of such an arrangement that a thermoplastic synthetic resin layer such as polyethylene, polypropylene or the like is laminated on the outermost layers of the front and rear of a paper board base, and, as necessary, a reinforcing layer such as an aluminum foil layer or a barrier type synthetic resin is laminated on a substrate. Furthermore, the lining member 3 may preferably be made of synthetic resin, and the pull tab piece 5 may preferably be one in which thermoplastic type resin is laminated on an aluminum foil, a sheet of polyester or the like. Fig. 2 is the sectional view showing the essential portion of the present invention, in which the lining member 3 has a portion 32 exposed from the through hole 2 being slightly raised relative to a flange portion 31 attached to the inner surface of the main body of paper container 1. The pull tab piece 5 is attached to the exposed portion 32 including the small through hole 4 of the lining member 3 and the outer wall surface of the main body of paper container 1 provided therearound. In this embodiment, one end of the pull tab piece 5 is free to be formed into a knob 51 without being attached to the outer wall surface of the main body of paper container 1, so that the free end advantageously serves as a turning point for opening. Furthermore, a half-cut line 6 is provided on the outer wall surface of the main body of paper container 1 along a boundary portion between a contact portion and a non-contact portion of the pull tab piece 5, during the opening operation, peel-off of the outer wall surface of the paper container is accompanied therewith and a trace of opening is clearly left, so that it is suitable for identifying the safety of the content. The shape of the small through hole 4 formed in the lining member 3 is not limited to one having a true roundness, but may be optionally selected from an elliptic shape, a poligonal shape, a tongue shape and the like. As for the pull tab piece 5 covering the small through hole 4, the shape is free, and the knob 51 serving as the turning point for opening may be positioned at any position provided upwardly, downwardly, righwardly or leftwardly of the small through hole 4. According to the present invention with the above-described arrangement, the tightly sealed paper container is simplified in construction, easily opened and suitable for pour-out operation. The opening device has a very small thickness, whereby the opening device can be secured to the flat board-shaped paper container ant applied to the filler machine as it is, so that there is no need of the reconstruction of the filler machine and the provision of an additional equipment. Furthermore, the shape of the opening device in the paper container is simplified, so that sterilization by the hydrogen peroxide gas can be easily performed, and moreover, the hydrogen peroxide gas can be easily removed after the sterilization. The surrounding of the through hole of the lining member is raised, so that the pull tab piece can be easily attached and liquid-extracting can be facilitated. Furthermore, the half-cut line is provided on the front surface of the main body of paper container along the boundary portion between the non-contact portion for the knob and the contact portion for the tight sealing, of the pull tab piece, so that the content can be held safe.

Claims: A tightly sealed paper container (1), wherein a through hole (2) is formed in a container material laminated with a thermoplastic synthetic resin layer provided at the outermost layers of the front and rear of a paper board base, a lining member (3) for providing a smaller hole (4) than the through hole (2) is so positioned within the container (1) to be in contact with the inner surface thereof around the through hole (2) and with the small hole (4) disposed in the through hole (2) of the container material and a pull tab piece (5) covering the through hole (2) of the container material (1) is in contact with the outer surface of the container, characterized in that said lining member (3) is a moulded part of synthetic resin, said small hole (4) therein is a through hole, and the part (32) of the lining member surrounding the small through hole (4) slightly projects outwardly from the front surface of the container material (1). A tightly sealed paper container as set forth in Claim 1, wherein a half-cut line (6) is provided on the outer surface of the container along a boundary between a contact portion of the pull tab (5) piece to the outer surface of the container and a non-contact portion of the pull tab piece (5) to provide a knob (51).

Inventors: YASUI, NOBUSHIGE C/O LIQUID PACKAGING CENTER
Applicants: JUJO PAPER CO., LTD.
Application year: 1989
Main classification: B65D5
IPC codes: B65D5