Container for strong drinks

A~ ~szo~ 1 This invention relates to a container ~or strong drinks and, more particularly, to a container for strong drinks, comprising an outer shell made of a paper sheet coated on both sides with a plastic material (hereinafter referred to as plastic-coated paper sheet) and, inserted therein, an inner vessel made from a polyester resin having an intrinsic viscosity of 0.5 to 1.4, said outer shell and said inner vessel being joined together around their openings to form an integral brim.

Japanese Utility Model "Kokai" (Laid-open) No. 5,572/1974 has proposed as a substitute for glass vessels a disposable vessel comprising a vessel made of uncoated paper sheet and, inserted therein, a plastic inner vessel having a thick rim and a thin-walled body.

Although suitable for the exclusive use as a receptacle for soft drinks, such a container may arouse problems when used for strong drinks. For instance, when filled with hot sake (Japanese fermented liquor made from rice) and then sub~ected to the showering treatment which is an indispensable next step, it is liable to become deformed owing to wetting of the paper sheet which is an essential component of the container.

Moreover, depending upon the type of plastics selected for the inserted vessel, the alcohol in the strong ~lSZO~l . - 2 1 drink exerts a solvent action upon the plastlc vessel to cause partial dissolution of some constituent of the plastic material or partial transfer of its odor to the strong drink resulting in deterioration of the flavor of .

the latter.

Under such circumstances, the present inventors made various attempts to develop a convenient container for the strong drink, which, when filled with an strong drink and stored for a long period of time, will keep the drink from permeation to the ou~side, odor transfer from the paper sheet or plastic material, contamination with the plastic material by dissolution and deterioration in delicate flavor, not to speaX of an agreeable aroma, of the drink and, in addition, which is improved in operational efficiencies in various phases of its handling such as fllling, shipping, transportation and storing. It was found, as a result, that the above ob~ect can be achieved by constructing a container ln such a way that an inner vessel made from a polyester having an intrinsic viscosity of 0.5 to 1.4 is inserted in an outer shell made of a plasticcoated paper sheet and both inner vessel and outer shell are ~oined together around their openings to form an integral brim.

A few examples of embodiments of the invention are illustrated below with references to the accompanying drawings in which:

Fig. 1 is an elevation, in cross section, of a container according to the invention; and Fig. 2 is an elevation, in cross section, of another embodiment of the invention.

Fig. 1 shGws the case in which the polyester 1~5201~ 1 vessel is inserted in close contact with the inner wall of a plastic-coated paper sheet shell. In the Fig. 1 1 is an outer shell made of paper sheet 2 coated on both sides with plastic material 3 and composed of body 4 and bottom 5, both being jointed to form an integral outer shell. 6 is a vessel made from a polyester having an intrinsic viscosity of 0.5 to 1.4 and is inserted in plastic-coated paper sheet shell 1 in close contact with the inner wall of the latter. The upper edge of body 4 of the plastic-coated paper sheet shell is flared to form flat flange 7 and rounded rim 8. The upper edge of polyester vessel 6 is also flared to form flat flange 9 approximating in pattern and size to the flange 7 and rounded rim 10. Both shell and vessel are assembled so that flange 9 is superposed upon flange 7 and the assembly is joined together by double seaming to integrate the shell and vessel along rims 8 and 10.

In the above example of the embodiment, the rlms of both shell and vesse' are in the form of flat flange. However, the rims are not limited to the flange form, but can be in beaded form. It is also possible to effect the integration by ~oining together the flanges of both shell and vessel with an adhesive instead of the double seaming.

Further, although in the above example the polyester vessel has a thick rim and a thin body wall in contrast to body 4 of plastic-coated paper sheet - 3 ~lS2011 1 shell 1, other structures are possible. In ~oining together the rims 8 and 10 by double seaming, the rim of polyester vessel 6, no matter whether it is beaded or in the form of flange, should have a thickness just sufficient to withstand the operation of double seaming, while the wall thickness of the body adjoining to the rim can be as small as a thin film sufficient for receiving the strong drink. Therefore, the construction shown in the above example is preferred. One of the suitable methods for fabricating such a polyester vessel is so-called vacuum forming or pressure forming of a polyester sheet having a thickness of the flange 9.

The structure of the plastic-coated paper sheet shell is not limited to that illustrated in the above example which is composed of the body and the bottom which are produced separately and bondqd together.

Fig. 2 shows an example in which some clearance 11 is provided between the inserted polyester vessel and the plastic-coated paper sheet shell. The numerical notation is the same as used in Fig. 1.

The plastic material to be coated on both sides of the paper sheet constituting the paper shell used in the container of this invention may be freely selected, because it does not come into direct contact with the strong drinks.

The polyester vessel used in this invention is made from a linear polyethylene terephthalate homopolymer or linear polybutylene terephthalate homopolymer -- 4 - :~:5201~.

1 consisting of recurring units o~ ethylene terephthalate or butylene terephthalate respectively, a copolymer comprising a small proportion of comonomer units in addition to the above recurring units, a blend of such homopolymers or copolymers, or a blend of such homopolymer and such copolymer.

The comonomers include dicarboxylic acid components such as isophthalic acid, adipic acid, sebasic acid, p-~-hydroxyethoxybenzoic acid, and alkyl ester derivatives thereof and glycol components such as ethylene glycol, butanediol, hexamethylene glycol, neopentyl glycol, and cyclohexanedimethanol.

The polyester vessel for use in the container of this invention can be fabricated by the method described in Japanese Patent Publication No. 5,107/1969 or No. 5,108/1969, in accordance with the use of the container, or by any other suitable method.

The polyester resin to be used as the material in fabricating the polyester vessel should have an intrinsic viscosity ln the range of from 0.5 to 1.4, preferably from 0.6 to 1.2. If the intrinsic viscosity is below 0.5, the resin has a low alcohol resistance and is not suitable for the container intended for long-term use; also, such a resin has a low impact resistance. Accordingly the polyester vessel is liable to become deformed even by a slight impact exerted during the operation of inserting it into the plastic-coated paper sheet shell. If, on the other hand, ,: ~ .

:~S201~ 1 the intr-insic viscosity exceeds 1.4, the moldability of the resin becomes insufficient for the fabrication of a vessel with uniform thickness. The intrinsic viscosity given above is the value determined at 25C in a solution of a phenol-tetrachloroethane mixture (1:1 by weight).

The strong drinks to be filled in the container of this invention include sake, whisky, brandy, gin, vodka, wine, cocktails, shochu and fruit wines such as plum liqueur and others.

As fully described above, since the container of this invention has an outer shell, including the bottom thereof, which is made of a paper sheet coated on both sides with a plastic material, the filled container retains its original shape even after sub~ected to the showering treatment which is a necessary step for the container filled with sake at an elevated temperature When the sake packed in the container is requested to be served hot, the filled container can be directly immersed in hot water without any harm.

When the sake is intended to be served cold, the filled container can be cooled or preserved in a refrigerator without causing either condensation of moisture on the outside surface of said container or deformation of said container due to moisture absorption, because the outer shell is made of a plastic-coated paper sheet.

The polyester vessel inserted in the plasticcoated paper sheet shell is made from a polyester resin ~15201~ l having an intrinsic viscosity of 0.5 to 1.4, which is excellent in mechanical properties and chemical resistance, particularly in alcohol resistance. As a consequence, the polyester vessel is substantially inert to the solvent action of the alcohol contained in the strong drink filled in the polyester vessel, the dissolved amount of the polyester being too small to affect the odor or taste of the drink. The polyester vessel is free from the adverse effect of a plasticizer or a residual monomer contained in the polymer on the human body as is the case with a polyvinyl chloride resin. Since the polyester vessel itself is odorless, it causes no change in aroma and delicate taste of the strong drink. Moreover, the polyester vessel has an extremely low permeability to oxygen and carbon dioxide and there is no fear of degeneration in the quality of strong drink caused by these gases.

Thus, it has now become possible to preserve strong drinks for a long period of time.

If a strong drink is filled in a container made of a paper sheet overlaid on one side with a plastic film, there will occur a phenomenon of oozing of the strong drink from the ~ointed part of the container, whereas the container of this invention is entirely free of such a phenomenon.

The fabrication of the container of this invention is performed with a high efficiency, because it is carried out simply by assembling the plastic . , - 7 il52011 1 coated paper sheet shell and the polyester vessel which are separately provided and integrating the assembly along the rims of both shell and vessel by a simple means. The finished container is much lighter in weight as compared with a glass vessel of the same capacity~ resulting in easier handling and improved efficiency in shipping, transportation and storing. The unprecedented features of the- container are the outcome of this invention.

-- 8 -