Bottles and jars – Closures – Cap type
Reexamination Certificate
1999-06-23
2001-07-17
Shoap, Allan N. (Department: 3727)
Bottles and jars
Closures
Cap type
C215S250000, C215S043000, C215S341000, C215S321000, C215S320000, C215S354000, C220S789000, C222S153060, C222S570000
Reexamination Certificate
active
06260723
ABSTRACT:
The invention relates to a package for flowable media with a snap lid, both of which are made from thermoplastic material, in which the collar-shaped head surrounds a pouring aperture, which has on the outside a retaining ring, on the inside an approximately annular internal surface, at the top at the free end an edge with a snap catch and which can be closed by means of the snap lid, from the inside of the closing wall of which an annular sealing lip projects towards the inside of the package, and can be brought into contact with the inside surface of the edge in a sealing engagement, and which has an outside catch for snap engagement with the edge of the head.
The invention also relates to an injection moulded blank for manufacturing a package for flowable media from thermoplastic material, in which the collar-shaped head surrounds a pouring aperture, and has on the outside a retaining ring, on the inside an approximately annular internal surface, and at the top at the free end an edge with a snap catch.
Injection moulded blanks made from plastics, in particular from polyethylene terephthalate (PET) are known. With blanks, and the packages formed from them, for example, bottles, a distinction is made between three different areas, namely the bottle head, the body and the base. The bottle head is also often moulded with a thread and with sealing surfaces. The bottle later inflated and filled is then closed with a screw lid. For aseptic closures, the screw lid either has on it sealing inserts, for example, foils, or the screw caps are moulded with special sealing lips which seal onto the cylindrical inside of the bottle head or onto the bottle edge.
Plastics snap closures are also known which also seal onto the inside of the mouth of the bottle. These snap closures are fitted, for example, when dealing with still mineral waters. Known snap lids of this type have a snap edge lying on the outside with a tapered seal lying on the inside. In this case the inside of the cylindrical head of the blank or of the bottle has no curvature along the axis of the cylinder.
Although in this way a seal is obtained with respect to liquids such as, for example, water or the like, with a low degree of capillary action, it is not obtained with respect to methanol or, for example, helium. Helium, as the smallest sized chemical element, is particularly well suited as a measuring medium for testing sealing. If an aseptically sealed closure is desired on a package for flowable media, such measuring methods can be used.
The object of the invention is to provide a package for flowable media of the type described in the introduction, the head of which can be closed in an aseptically sealed manner with the snap lid; and the provision of an injection-moulded blank, as already described hereinabove, from which a package of the type described can be manufactured, wherein the head on the blank is not altered during the process of manufacturing the package.
In accordance with the invention, the object is solved with respect to the package for flowable media in that the head of the package widens radially outwards and upwards at its edge, and both the inner surface of this edge and the outer surface of the sealing lip on the snap lid are curved convexly in the direction of view towards these two surfaces. It is firstly to be explained that the pouring aperture and thereby the head of the package is arranged on the side of the package opposite the base on which it stands, namely “at the top”. The free end of the head is thus located at the top, where the edge with the snap catch described is arranged. On the upper free end, the pouring aperture can be closed by means of the snap lid described, which in cross-section has substantially a U-shape, wherein the segment joining the two free legs of the U is the projection onto the closing wall.
Corresponding to the generally circular configuration of the pouring aperture, the closing wall is a flat, round disc which preferably is substantially planar. Onto its annular periphery an outer ring is connected by means of a curve, which ring provides enclosure of the edge of the head. The outer ring can be tilted slightly with respect to the edge of the head, for example, at an angle of 5 to 10°, preferably approximately 20°. At the outer lower end of the outer ring a closure safety device is fitted, which optionally provides retention of the snap lid on the head by means of a catch on the head of the package.
Such a snap lid is clamped onto the edge of the package and can be snapped into place particularly well at its free end in that the head of the package widens outwardly and upwardly. The diameter of the edge is thus on average greater at the upper free end of the head of the package than the diameter of the pouring aperture.
This radial widening of the edge outwards and upwards provides for an inner surface of the edge. Looking towards this, the curvature is convex.
If the snap lid is viewed, and if seen from inside towards its closing wall, the sealing lip is projecting from the closing wall opposite to the direction of viewing, that is to say inwards, is then evident. The diameter of this is determined in relation to the centre of the snap lid from the outer surface of the widening edge of the package head. The edge and the sealing lip should namely be brought into mutual sealing engagement with one another. With this, the outer surface of the sealing lip plays a particular role, and according to the invention it is curved such that it appears convexly curved when viewed at an angle from outside towards the outer surface of the sealing lip. The curvature of the inner surface of the edge on the head and the curvature of the outer surface of the sealing lip on the snap lid are thus curved in opposite directions to one another. These two surfaces come to lie on top of one another when the snap lid closed, and, in accordance with the teaching of the invention, by means of the convex curvatures a sealing line is produced. In other words in cross section along the pouring aperture, the two curved lines touch at a point. This point is the projection of the line which extends along the sealing lip or along the edge of the head. This linear touching allows the aseptically sealed closure of the head with the snap lid described.
Bacteria and spores are generally a magnitude larger than helium atoms and can thus pass through a helium tight seal less than helium atoms. Two criteria have been established for defining aseptic sealing according to the invention: The first criterion requires sealing against helium. The second criterion for an aseptically sealed closure necessitates the sealing surfaces being sterilisable. An aseptically sealed closure within the meaning of the teaching according to the invention is thus a closure sealed at least with respect to methanol, preferably even sealed with respect to helium. This condition is ensured by the solution according to the invention.
It is also particularly advantageous when in addition the sealing surfaces of the aseptically sealed closure can be sterilised well. This is ensured particularly well, inter alia, when the surfaces of both the edge of the head and of the snap lid facing towards the inside of the pouring aperture have surfaces which are as smooth as possible. In accordance with the invention, this is provided in that the surfaces facing towards the inside of the package have no, or almost no, undercuts. The sterilising processes then work particularly well. The skilled person understands that an edge widening radially outwards and upwards on the one hand, and a snap lid with a sealing lip projecting downwards on the other hand make possible smooth surfaces without undercuts.
The sealing between the head of the package and the snap lid is, in the case of the invention, tested by means of two different mechanisms, which will be referred to hereinafter as macrological sealing and micrological sealing. It may be sufficient when the micrological sealing is measured and obtained, for the sealing of a head of a package of t
Dunn Michael L.
Hylton Robin A.
Shoap Allan N.
Showalter Robert L.
Tetra-Laval Holdings & Finance
LandOfFree
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