MXPA97000480A - Paper composite for making packages for liquid or granular products - Google Patents

Abstract

Paper composite for realizing three-dimensional packages characterised in that it consists of a layer of yieldable paper (4) having a degree of yieldingness in any direction not lesser than 10 percent and of at least an impermeabilizing film (6) having yieldingness compatible with that of yieldable paper.

Description

MATERIAL COMPOSED OF PAPER TO MAKE PACKAGES FOR LIQUID OR GRANULATED PRODUCTS DESCRIPTION OF THE INVENTION This invention relates to a composite material of paper for making three-dimensional packages for products possibly solidifiable in the liquid state, or for granulated or powdered products, a method for carrying out said packages and a package obtained through the method. Methods for packing, in measured quantities, possibly solidifiable liquid products, or granulated or powdered products for consumption are known. In one of these methods, medium boxes of substantially rigid plastic material, for example, polypropylene, are thermoformed and joined together along their edges to form a cavity, which can then be filled by a traditional filling machine. If the product to be used is in the liquid state, granulated or powdered state, the package obtained in this way is ready for sale after sealing. However, if the product to be used is in a solid state (eg, ice cream), after the filling operation, the filling with the liquid product and the sealed package is, refrigerated and preserved under refrigeration conditions until your consumption Regardless of the nature of the packaged material, these known packages have the advantage of being able to be formed in practically any configuration, but also have certain disadvantages, and in particular: - a considerable cost, related to the cost of the plastic material used, practically no merit ecological, presenting the non-biodegradable nature of the plastic used, some weight, with consequent costs for transportation, - a space requirement after use, since the package used can not be substantially reduced in volume compared to the total package. It is also known to pack generally liquid products using a continuous tubular element of cardboard coated with polythene or bipoliteno, which is filled in separate portions by transverse welds, cross-sections that are made through said welds. The package generally has a tetrahedron, parallelepiped or cylinder shape, depending on the manner in which the transverse welds are made and the bending operations to which the package can be subjected after its separation from the continuous tubular member. This known method considerably speeds up packaging operations, but has certain limitations both in terms of obtainable shapes, as well as overall package dimensions after use, and costs. An object of the present invention is to eliminate such disadvantages and obtain a composite material to form parcels measured, in practically any way, for products in a liquid, granulated or powdered state, which has a low cost. A further object of the invention is to obtain very light packages, in order to minimize packaging and transportation costs. Another object of the invention is to provide a method that allows the package to be reduced to a minimum volume after use. A further object of the invention is to provide a method that allows the use of commercially available, traditional packaging equipment. All these objects are obtained according to the invention through a composite material of paper to form packages in a three-dimensional manner, as described in claim 1.

The invention also relates to a method for obtaining packages according to claims 5 to 21. The package thus obtained is claimed in claims 22 and 23. The present invention is described in more detail below with reference to the accompanying drawings, in which: which: Figure 1 shows an enlarged sectional view of a portion of a paper composite material according to the invention; Figure 2 schematically illustrates a line for implementing the method of the invention; Figure 3 is an enlarged perspective view of the open mold of Figure 2; Figure 4 is a vertical section through a closed mold during the stage preceding the introduction of the pressurized fluid; Figure 5 shows the same view as in Figure 4, but during the stage after the introduction of the pressurized fluid; Figure 6 is a perspective view of a package removed from the mold and waiting to be filled; Figure 7 shows schematically in a cross-sectional view, an open mold for implementing the method in a different embodiment; Figure 8 is the same mold of Figure 7 in a further embodiment, and Figure 9 shows a package removed from the mold and waiting to be filled. As can be seen from the figures, the paper composite 2, according to the invention, consists of a deformable paper layer 4 and a waterproof plastic film 6. The deformable paper 4 has a degree of elasticity, such which allows it to be permanently extended transversely and longitudinally by at least 10%, and preferably 20%, and especially to such a degree that the desired final configuration can be obtained without laceration of the package. The plastic film 6 is preferably of polyethylene or other possibly removable thermoplastic material, with a degree of elasticity not less than that of the deformable paper layer to which it is coupled and with suitable characteristics of welding capacity. The bond between the two layers 4 and 6 is preferably formed continuously by traditional methods, which do not form part of the invention and will not be described further. In the embodiment illustrated in Figure 2, the composite material 2 is wound around a rail 8 and is bent longitudinally so that the two layers of polythene 6 are confronted.

In the embodiment shown in Figures 2-4, the method of the invention also utilizes a mold formed from two mold halves 10 that move relative to each other, and that each comprises a cavity 12 limited by a ring 14 slightly projecting, comprising an interruption 16. The cavities 12 of the mold halves 10, the projection rings 14, which limit them and the interruptions 16 in the projection rings 14 perfectly coincide when the two mold halves 10 they get in touch In the drawings, the two mold halves 10 are shown for simplicity with a single print, while, during practice, it is preferable to use multi-print molds to speed up packaging operations. It can also be seen that the cavity 12 of each mold half 10 extends externally towards a duct 18, which opens towards the interruption 16 provided in the ring 14, limiting the cavity 12, and coincides with the adjacent duct of the other mold half 10. The method of the invention is as follows: after the composite material 2 has been folded longitudinally into two parts and has been placed in this folded state between the two mold halves 10, these are joined with in order to hold it between them (see Figure 4). The two contact rings 14 are then heated to be thermowelded together with the two layers of polythene 6 lying between them, but with the exception of the interruption 16. After the thermowelding has been carried out, compressed air is introduced through the duct 18, said air can also be hot, with the dual purpose of heating the polythene 6 in order to soften and sterilize it, and to stretch the two sheets of the deformable paper 4 retained between the rings 14 to cause these and 'j.0 to adhere to the surface of the respective cavity 12 (see Figure 5). The stretching of the paper is facilitated by the softening of the polythene. After this insufflation step, the two mold halves 10 are separated to allow the removal of the pack 20 of internally waterproof paper, having a configuration corresponding to the cavities of the two mold halves 10, this configuration being stable due to the permanent deformation to which the deformable paper 4 and the polythene 6 forming the composite material have been subjected (see Figure 6). Then, this package can be transferred to the filling stage, which is preferably carried out with automatic machines, and then to the sealing step of the polythene 6 in the interruption 16, through which, the product to be packed is inserted, the product can be liquid, in paste, granulated or in powder. Depending on the nature of this product, package 20 once sealed, may be subjected to another treatment or transferred to storage. For example, if the product is to be consumed in a liquid state (shampoo, detergent, milk, water, etc.) or in a granulated or powdered form, it can be stored directly. If the product has been temporarily heated to bring it to a liquid state, even if it is liquid at room temperature (chocolate, or cheese, or soap), it is enough to wait until it cools down so that it can assume and maintain the shape of the package 20, which occurs after it has been removed for consumption. However, if the product is a liquid for preparing an ice cream or caramel ice cream, it has to be frozen after filling, however, this can be done just before consumption. In summary, independently of the product to be packaged, this first embodiment of the method according to the invention is based on the principle of using polythene, the traditional purpose of this is to waterproof the deformable paper against the liquid product during its filling and storage, but also waterproof the paper against the air, in this way allowing the paper to be subjected to an operation, which previously was not possible. If it has been observed that the package can receive an extensive moisture deposit (condensate), it is preferred that the deformable paper layer 4 comprises a polythene film 6 on both of its surfaces. A second embodiment of the method according to the invention says that, after the thermo-welding of the polythene, the fluid fed under pressure through the duct 18, is not air, but rather the actual liquid product is packed, causing the paper it stretches until it adheres to the walls of the two mold halves 10. Again, in this case, the product to be packed can be treated variously depending on its nature, but in all cases, the invention comprises the formation of the package inside the mold by the actual product that is going to be packed. If this product is solidifiable, that is to say if it is solid at room temperature, but has been previously heated to facilitate its filling, or if it is liquid at room temperature, but will be cooled / after filling, the invention implies a mutual action between the liquid and the package. In this respect, during the filling, the liquid product forces the paper and the polythene to assume the shape imposed by the mold within which it is stored, while during the solidification it is the package, previously formed by the liquid, which constitutes now the mold for the liquid during solidification. Furthermore, in both embodiments of the method according to the invention, in particular for packaging edible solidifiable liquid products, the filling step can be preceded by inserting a traditional stick 21, for example, wood or plastic, into the mold, for remain retained by the product as it solidifies and forms the necessary support for products held by hand. A third embodiment of the method according to the present invention provides that the sheet of the composite material 2 causes the paper layer 4 to face the cavity 22 of a mold 24 and then be limited in correspondence of the continuous edge of this cavity. Subsequently, the mold 22 is subjected to depression through a suitable suction channel 26 provided therein, in order to cause the tangential stretching of the composite material to obtain its adhesion to the internal surface of this cavity. In order to obtain a better stretch it can be seen that a complementary punch 28 looks at the cavity 22 of the mold, which, during the suction step, contributes through a mechanical form, to carry out the stretching of the paper .

It is preferred that said mechanical effect be supported by a pneumatic effect, and for this purpose, the punch 28 is provided with a plurality of channels 30, through which it is possible to direct an air jet, if desired hot, against the sheet of composite material. The valve-shaped package 32 thus obtained can be filled with the product to be packed and subsequently closed by thermowelding a transparent film 34 or a complementary valve. In any case, regardless of the modality used, the composite material according to the invention and the method for carrying out the desired packages have considerable advantages, and in particular: they allow the formation of packages practically without any limitation with respect to their shape , - allow the use of commercially available training and filling equipment, traditional, - allow very light packages to be formed at low cost, which can be reduced to a minimum volume after use.

Claims (23)

1. A material composed of paper to obtain three-dimensional packages, characterized in that it consists of a deformable paper layer having a degree of elasticity in any direction of not less than 10% and of at least one waterproofing film having an elasticity compatible with that of the deformable paper.

2. A composite material according to claim 1, characterized in that the waterproofing film consists of a thermoformable and heat-sealable material.

3. A composite material according to claim 2, characterized in that the waterproofing film consists of polythene.

4. A composite material according to claim 1, characterized in that the waterproofing film consists of an aluminum alloy.

5. A method for obtaining packages through the paper composite material according to one or more of claims 1 to 4, characterized in that a sheet of the composite material faces the cavity of at least one mold, the sheet being limited in correspondence of the Continuous edge of the cavity and subsequently the tangential stretching of the sheet of composite material is carried out, so that it adheres to the internal surface of the cavity, and a concave valve is obtained, having the shape of this cavity, to be sent to the next filling and closing steps.

6. A method in accordance with the claim 5, characterized in that the stretching of the sheet of the composite material is carried out for the depressurization caused between it and the internal surface of this cavity.

7. A method in accordance with the claim 5, characterized in that the stretching of the sheet of the composite material is carried out by mechanically pushing the sheet into the cavity by means of a punch having a shape substantially complementary to that of the cavity.

8. A method according to claim 7, characterized in that the mechanical effect is supported by a pneumatic effect by insufflation, through the punch, of a jet of compressed air against the sheet of composite material.

9. A method according to claim 8, characterized in that hot air is used.

10. A method according to claim 5, characterized in that after filling, the concave valve is closed with a sheet of heat-sealable material applied to its edge.

11. A method according to claim 5, characterized in that after filling, the concave valve is closed with another placed turned on the first and welded thereto near the touch edges.

12. A method according to claim 5, characterized in that: two sheets of composite material are brought into contact, so that thermoformable, thermoformable plastic films are in mutual contact, - the two sheets are welded together along a line perimeter of a predetermined pattern comprising at least one interruption, - a pressurized fluid is introduced through the interruption to the interspace limited by the sheets maintained between the two closed mold halves, between which a cavity limited by the perimetral welding line, in this way to stretch the sheets so that they adhere to the walls of the cavities, - the volume limited by the sheets is filled with the product to be packed, and - the perimeter line welding is completed through the interruption.

13. A method according to claim 12, characterized in that the two sheets to be joined are obtained by longitudinally bending a continuous band.

14. A method according to claim 12, characterized in that the two sheets are welded together around the perimeter line by thermowelding.

15. A method according to claim 12, characterized in that the two sheets are welded together along the perimeter line by ultrasound.

16. A method according to claim 12, characterized in that the sheets are welded together while they are retained in the two mold halves.

17. A method according to claim 12, characterized in that the two half molds are kept hot while the fluid is injected.

18. A method in accordance with the claim 12, characterized in that by using the sheets consisting of a deformable paper layer bonded to the two plastic films applied to both sides thereof.

19. A method in accordance with the claim 12 and / or 17, characterized in that the fluid is compressed gas.

20. A method according to claim 19, characterized in that the fluid is hot compressed gas.

21. A method according to claim 12, characterized in that the fluid is the actual product to be packed.

22. A package obtained through the method according to one or more of claims 5-21, characterized in that it consists of a concave container, on the edge of which a closing film is applied after filling.

23. A package obtained through the method according to one or more of claims 5-21, characterized in that it consists of two concave valves joined together along the confronting edges.