The invention relates to a parallelepipedal flat-gabled package, especially an eared package with a medial seam, with an area in the gable that has been prepared such that it can be penetrated or separated along a closed curve and, once it has been penetrated or separated, will constitute a pouring hole, with a plastic pour-out structure that has a flange surrounding the pouring hole, rigidly secured to the outer surface of the gable, and into the spout of which can be axially inserted a tube with a circumference that matches the closed curve and with a number of triangular teeth along the surface that faces the pouring hole, and with a cap that can be repeatedly employed to close the spout, the inner surface of the package being coated with a hot-adhering film of plastic. The invention further relates to a method of manufacturing such parallelepipedal flat-gabled package.
Such conventional parallelepipedal packages as the Combibloc and Tetra Brik for example that are known from the state of the art and commonly employed for packaging liquids in conjunction with conventional cold, cold-sterile, hot, and aseptic filling, cannot be closed again once they have been opened.
Punching a pour-out and air-admission hole through the gable of a flat-gabled package during the manufacturing process and sealing it on both sides with a thin sheet of material has accordingly been proposed (EP No. 0 214 791). This system also involves a special intermediate layer that allows the package to be reclosed with an adhesive pull tab.
Once the package has been reclosed, however, it will no longer be either hygienic or tight due to traces of product that adhere to the intermediate layer subsequent to pouring, and it will even be impossible to reclose if the product is highly viscous.
Also known from the dairy journal Welt der Milch 40 (1986), 23, 696 is a flat-gabled package with a plug-like closure articulated to the top of the gable with its walls tapering toward the front. The plug can be inserted into and retracted out of a pour-out opening in the gabled top of the package, for which purpose its upper closure surface is provided with a ring and a tab.
A closure of this type cannot of course ensure adequate tightness because the plug cannot be reliably positioned against the relatively soft laminating material at the edge of the pour-out hole. Furthermore, even a low level of pressure against the ringed tab can cause the package to open unintentionally. Add to this that the vicinity of the pouring spout will no longer be hygienically covered once the package has been opened and that, at least if the product is highly viscous, the remainder will not readily flow back into the package once the pouring process has been completed, but will settle on or drip uncontrolled from the surface of the gable.
The same drawbacks are characteristic of the closure system described in U.S. Pat. No. 3 924 777, which also does not provide a continuous inner coating over the vicinity of the opening that is absolutely necessary for gas-tight and odor-tight packages.
It has in particular been necessary up to now to accept that non-gurgling and drip-free pouring cannot be attained with flat-gabled packages.
EP No. 0 167 095 A2 proposes a sloping-gabled package with a spout and snap-on lid integrated into a plastic pouring structure introduced into a punched-out hole in the gable from inside and sealed on the inside against an outside support. This approach, however, ensures only moderate sterility due to the blisters that can occur if the seal is not full-surface.
Known from in German No. 3 039 299 A1 is a sloping-gabled container with a three-part pour-out structure secured to the surface of its gable. The structure consists of a flange sealed to the surface of a cylindrical section perpendicular to the flange with a pouring tube that is divided on the inside by an L-shaped partition and slides back and forth axially inside its inner surface, and of a cap that can be applied to the upper end of the perpendicular section. The container is opened by removing the cap and forcing the inner pouring tube down until triangular teeth on its face penetrate the side of the gable. The penetration is limited by a terminating edge on the pour-out structure. This embodiment, however, is unfortunately very expensive.
However, since flat-gabled packages are intended to be stacked one on top of another, this requirement alone prevents the solutions employed for sloping-gabled packages from being applied to them. Another circumstance that prevents applying the principles to flat-gabled packages is that they must satisfy different requirements with respect to controlling and directing the flow of poured-out product.
Another unsatisfactory feature of the pour-out structure described in EP No. 0 167 095 A2 is its relatively small pour-out opening, which is not appropriate for highly viscous liquids.
Other drawbacks of the reclosable pour-out structure known from German No. 3 039 299 are that, since it opens toward the inside of the package, it can only be sterilized at great expense and risk along with the package itself and cannot be provided with a continuous inner coating to cover the vicinity of the pouring opening before the package is opened.