Package making – Methods – Forming a cover adjunct or application of a cover adjunct to...
Reexamination Certificate
2003-05-27
2004-12-21
Sipos, John (Department: 3721)
Package making
Methods
Forming a cover adjunct or application of a cover adjunct to...
C053S451000, C053S456000, C053S133200, C053S547000, C053S551000, C053S567000
Reexamination Certificate
active
06832462
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to a process for making flexible or squeezable containers, preferably tubes. The invention also relates to the tube blank produced as a result of the said process and also to resulting sachets and filled tubes.
2. The Related Art
Tubes are cheap and easy to use containers for flowable substances, especially for viscous liquids and pastes. Whether for comestibles, medicaments, washing compositions, cosmetic substances or glues a tube comprises a bag, which defines a reservoir for containing a substance and a dispensing assembly for dispensing said substance. Commonly, it also comprises a means for re-sealing the tube which is usually associated with the dispensing assembly.
Considering their simple nature the apparatus for making a tube is often complex and expensive. It is usual that one piece of apparatus makes the tube, a further piece of apparatus attaches a dispensing assembly and further pieces of apparatus fill and perhaps a further device for sealing it. This requires that there is yet a further piece of apparatus for transporting the tube being formed between the different pieces of apparatus. The partially formed tube must be strong and rigid enough in its partially formed state to be transported and handled. In many cases partially formed tubes are stored and/or transported in this condition.
Such a chain of events dictates that producing a product packaged in a tube is a lengthy and complicated process.
Commonly, tubes are manufactured from a single sheet of material, which is typically a plastic, often a laminated plastic. The sheet is cut, wrapped around a mandrel and sealed longitudinally to form a cylindrical tube hose. This hose is usually cut to length and taken off the mandrel before being stored for further processing.
A dispensing assembly is usually attached before the tube is filled and sealed although this is not necessarily the case with sachets. Here it is more usual for the bag to be sealed at three of the four edges before being filled and then sealed and provided with a dispensing assembly.
Typical of the prior art is DE 44 29 148 which discloses a method for manufacturing, filling and sealing tubes. The method requires that a tube hose is formed around a mandrel, sealed at one end and then cut to produce an empty cylindrical container open at one end. This is then transferred to a second mandrel which fills the container and moulds a dispensing assembly before fitting a cap.
U.S. Pat. No. 3,354,601 (Schneider) describes a method for making a tube comprising forming a tube hose around a mandrel and then abutting a dispensing assembly upon the mandrel. The tube hose is then advanced into contact with the dispensing assembly before the mandrel is withdrawn. The tube hose is then welded onto the dispensing assembly. The tube blank is then transported to a separate filling machine.
It is an object of the present invention to reduce the time necessary to produce such a product thereby reducing costs and improving productivity.
SUMMARY OF THE INVENTION
Accordingly, the first aspect of the present invention provides a process for the manufacture of a tube blank, comprising the following steps:
(a) forming a tube hose around a mandrel and advancing the said tube hose along the said mandrel such that a leading edge of the said tube hose is flush with a leading face of the said mandrel;
(b) presenting a dispensing assembly to the said leading edge of the said tube hose;
(c) sealing the dispensing assembly with the said tube hose to form a tube blank;
(d) separating the tube blank from the mandrel.
DETAILED DESCRIPTION OF THE INVENTION
By tube blank is meant a flexible container with a first and second end, which first end is closed with a dispensing assembly and second end is open.
By tube hose is meant a tubular container, preferably a more or less cylindrical container, which is capable of serving as the bag portion of a tube or sachet when adequately sealed.
The first stage of the method requires the formation of a tube hose around the outside surface of a mandrel. The material for the tube hose is fed from a supply, usually a reel, where it is guided around a mandrel as described in EP-B1-0 719 634. In EP-B1-0 719 634 the hose are sealed longitudinally and cut and sealed transversely to produce container blanks. However, in the present invention the tube hose is maintained around the mandrel until the dispensing assembly is fitted. More specifically, the hose is advanced along the mandrel such that the leading edge of the tube hose is flush with the leading face of the mandrel. Accordingly, when the dispensing assembly is registered with the leading face of the mandrel it also sufficiently contacts the leading edge of the tube hose such that sealing between the dispensing assembly and the tube hose can occur. It is noted that it is the intention of this invention to simplify the process for manufacture of tubes and so it is preferred that the tube hose is formed around a mandrel and the tube hose material is fed from a supply and longitudinally sealed around the mandrel and not pre-fabricated.
In the present invention the longitudinal seal is formed by a convection or conduction heating-means. Preferably the heating means presses the tube hose margin overlap onto the mandrel. The subsequent heat forms a weld. Optionally, a co-operating heated section is provided on the mandrel so that the tube hose margin overlap is heated from both sides.
Any material suitable for forming a tube or sachet may be used in the present invention. The choice of material will be governed partly by the properties of the product to be contained in the tube and partly by the physical requirements of the tube both during processing and after filling. As explained below the process of the present invention allows greater flexibility in the choice of material by removing some of the constraints on tube properties during the forming and filling process.
Tubes are commonly formed from thermoplastic materials. Often thermoplastic laminates containing one or more layers of metal foil are used. Such thermoplastic sheets and laminates are commonly sealed together by heat welding. However, the process of the present invention is not limited to the use of thermoplastic sheet to form tubes or to the use of heat welding to form seals. Other materials, such as for example metal foils, can be used and joints formed using contact and/or heat sensitive adhesives applied to the overlap regions. It is also envisaged that a folded seam can be produced as the sheet of material is applied to the mandrel and that this folded seam be compressed by the heating means described above, optionally with the heating turned off.
It has been found that the process of forming the tube hose in this way can be improved by a multi stage welding process. Preferably, the heater which produces the weld is sized such that its length corresponds to a number of times the desired length of the final tube blank. In continuous operation the heater is thus applied to the seam for a fraction the time normally required to form a complete weld for each individual tube hose blank. The heater is then removed and the tube hose indexed by one final tube length. The heater is then re-applied. A first section of the heater contacts the tube over the partially formed weld and completes the weld. A second part of the heater helps form the partial weld on the next tube to be formed. Subsequent sections of heater form earlier partial welds. Normally, a two-stage welding process is sufficient. In this way the cycle time to form a tube can be reduced by up to around 50%.
If, as is preferred, the tube hose material is fed from a reel it is also necessary that it is transversely cut at an appropriate moment. This can be done at any time after forming around the mandrel but it is preferred that it is done at the same time that the tube hose is being longitudinally sealed or soon afterwards.
It is to be understood that the term mandrel is meant a device for support
Peacock Adam
Stamp Kevin John
Honig Milton L.
Sipos John
Unilever Home & Personal Care USA Division of Conopco, Inc.
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