Manufacturing container or tube from paper; or other manufacturi – Container making – Pliable container
Reexamination Certificate
2000-01-11
2001-07-17
Gerrity, Stephen F. (Department: 3721)
Manufacturing container or tube from paper; or other manufacturi
Container making
Pliable container
C493S218000, C493S193000, C493S196000
Reexamination Certificate
active
06261215
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention concerns a stable, standing, essentially rectangular form of a pack made from thin film or membrane-like material which uses a minimum of film area in relation to the volume of the contents of the pack and which because of its structural form can also use thinner film or membrane material than existing standing pouches, and to which various known and new types of top designs can be applied to facilitate opening and resealing or reclosing.
Further, the invention is concerned with a pack design that can be filled and sealed at high speeds comparable to the filling and sealing speeds of metal cans and glass jars, this ability being achieved by the special form of the base of the invention taken together with the method of manufacture of the pack which achieves an open box-like form that is stable and capable of being handled and transported at high speeds by means of conveyors.
Many forms of thin film or membrane packs are known, amongst them several forms of standing pouches. Concerning standing pouches, all of them have complex forms in the area of the bottom or base of the pack, such forms being necessary to give the pack some form of standing stability, particularly when filled with liquids. Because of these complex base configurations, all of these packs use more film or membrane than the invention, for a given filled volume. Moreover, some of these existing pack forms have vertical stiffening ribs to lend stability to the pack, but this stability is weakened in some cases by the method of folding the sides under to form the base of the pack, and in other cases by the means with which the walls are joined to the base, with the result that a stiffer film or membrane must be used to achieve the desired stability.
In regard to filling and sealing, all of these existing forms of standing packs use handling, filling and sealing systems which were developed specifically for known film type structures and which utilise single or up to about four filling heads which in turn limit the rate at which they can be filled and sealed to about 120 units per minute. This rate has been acceptable for the markets found for such packs but which is not acceptable for the high volume packaging required for many mass produced food and other products where rates of up to 2000 units per minute are required. Such high rates can only be achieved by multiple head rotary and in-line filling systems such as are used for the filling of bottles, jars and cans, which pack forms are in themselves stiff, stable standing packages exhibiting the necessary form stability for high speed handling. To date, no means has been found to utilise the existing forms of thin film flexible packs in such filling systems.
With recent progress in the development of special films capable of withstanding the high temperatures used in the cooking or autoclaving of food products packed in jars and cans, it is now possible to consider the use of thin film packs for such products, but it is not possible to achieve the required filling rates as explained above.
SUMMARY OF THE INVENTION
The invention provides solutions to overcome the limitations of existing thin film flexible pack forms in that it provides a thin film flexible pack that uses less material than existing forms in a form which can be handled and filled at much higher rates than existing packs. The pack can also be manufactured and filled and sealed on machines that are in many ways similar to known vertical form, fill and seal machines, and on variations of horizontal batch filling and sealing machines. The production rates at which these machines can produce filled and sealed packs is however slower than when multiple head rotary machines are used.
The invention is a pack that is manufactured in an open cubic-rectangular form and before it is filled and sealed consists of four rectangular walls which are integral with the base of the pack without requiring any form of join between the walls and the base.
The side walls are joined to the front and back walls at the vertical corners of the pack by heat sealing or by adhesives or other known joining means, such that the joins form vertical stiffening ribs as is known in the art, such stiffening ribs having a width of up to 10 mm or more but typically about 3 mm to 8 mm. In its preferred form, the base consists of a single layer of film or membrane, integral with all four walls and in a variation, consists of a double layer, with each layer separately integral with two walls, but when joined together, integral with four walls.
In its preferred form, the pack is constructed from a single layer of flat film or membrane in pre-cut or on-the-roll form laid out on a work surface where a vertical mould, with cross-sectional dimensions the same as the required inner cross-sectional dimensions of the pack, is placed over that portion of the film that is to form the base of the pack and against the vertical sides of which the film portions that are to form the vertical walls of the pack are pressed by upwardly folding the portions of the film that are to form the walls of the pack. At the vertical lines where the extremities of each wall are in contact with the adjoining walls, that is at the vertical corners of the pack, the film or membranes of the adjoining walls are joined together to form vertical stiffening ribs.
The pack which is now in its cubic-rectangular form, can now either be filled through the vertical inner form which would be the case when vertical form, fill and seal methods are employed, or when modified batch filling and sealing methods are employed, and then sealed at the top, or preferably removed from the form and transported to a filling station and there filled and later sealed. This is preferable because by this means one can produce filled packs at a higher production rate, utilising multiple formers and multiple stationary or rotating filling stations, than is otherwise possible by filling through the vertical inner form and then sealing. In both cases the sealing at the top can be carried out by means known in the art or by means hereafter described.
Examples of thin film or membrane-like materials that can be used for the manufacture of such a pack include low density polyethylene films, coextruded or laminated high density and low density polyethylene films, or co-extruded or laminated combinations of polyester, polyethylene, aluminum foil, paper, polyamide films, plus various vapour barriers films such as SiO
3
, amongst others.
The thickness of such films or film combinations can vary from 20 microns up to 200 microns or more.
Techniques for sealing the joins necessary to form the pack and to form any of the various top sealing formats include heat sealing, ultrasonic sealing, and adhesives.
A further means of constructing the pack is possible as a variation to the foregoing and as is later described herein, being a means whereby two strips of the film or membrane material are laid out at 90° to one another with one strip overlapping the other to form the shape of a cross, whereby the width of each strip is equal to the width of the wall plus the widths of the joining areas, and the length of each strip is equal to twice the length of the wall plus the width of the base measured in the long direction of the strip.
The two strips are joined together at the extremities of the overlap by adhesives, ultra-sound or heat sealing, with the provision that where heat sealing is employed, the overlying strip has heat sealable material on both sides of the strip.
The resulting form of the joined together strips is a cross similar to the previously described pre-cut form and can be formed into the described cubic-rectangular form as described.
This variation has the benefit of significantly reducing the raw film materials usage, in that there are no off-cuts or waste.
The invention is preferably a pack made from thin film or membrane like material with a base made of a single layer of said film/membrane that is conjunctional/integral with all four walls of the pack, ad
Chadbourne & Parke LLP
Gerrity Stephen F.
Tawfik Sam
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