ITBO950026A1 - METHOD FOR MORTGAGE FIXING OF SYNTHETIC RESIN ELEMENTS - Google Patents

Abstract

Method for the mutual fixing by heat-sealing of elements of synthetic resin, for example of flaps 17 to walls 18 of a container 2, made starting from a flat blank 1 in a flattened configuration. The method foresees the preventive heating of the internal facades 17a, 18a of said flaps 17 and walls 18, destined to mutually fit together. by the first hot air heating means 60. In the same way the facades 21a of inserts to be fixed to the walls 2a of the container 2 are heated by second heating means 70. Subsequently the facades 17a 18a are made to match, as well as the facades 21a and the walls 2a, and are respectively applied to them first pressing means 80 and second pressing means 90, suitable for exerting uniform stresses to allow heat sealing of the same.

Description

METHOD FOR THE MUTUAL FIXING OF SYNTHETIC RESIN ELEMENTS.

DESCRIPTION OF THE INVENTION

The present invention relates to a method for fixing, by means of heat sealing, synthetic resin elements which mate, overlap or side by side, and in particular for the heat sealing of the walls of blanks, intended to be transformed into as many boxes or boxes.

It is known that the production of box-shaped or box-type containers with plastic materials, such as synthetic resins, usually takes place starting from blanks obtained with sheets of such materials, solid or alveolate, produced in a flattened configuration. These are suitably shaped and furthermore affected by transverse and longitudinal creases, which define as many fold lines for the formation of the container itself.

When the latter is produced, the relative blank is folded by suitable equipment, according to known methods, until it assumes the shape of the container. In this configuration, some portions of the blank overlap, and must be kept mutually matching and fixed together to give stability. to the container, and allow it to keep the shape set. Sometimes, external inserts must also be added to the blank, equally made with synthetic resin, to define its shape and reinforce parts that are particularly subject to stress.

Such fixing is usually obtained, for the materials in question, by gluing the surfaces to be joined, by applying metal stitching points, or by heat sealing. The latter is for example made by means of ultrasonic devices, which are equipped with pairs of opposing pointed terminals, which clamp the overlapping sheets from the outside like pincers, and therefore emit ultrasounds at high intensity. controlled and for a predetermined time. There? ? sufficient to weld them by local melting of the synthetic resin of which these sheets are made.

The fixing methods described above have some drawbacks. The gluing process, for example, while allowing to obtain a functional and pleasant product, requires the use of foreign material, precisely the glue. There? can make it difficult to completely recycle the container after use. In fact, one of the main advantages related to the use of plastic materials is the possibility? of their total recycling and subsequent reuse, which on the one hand limits their environmental impact, and on the other makes them economically more? convenient.

Equally, the presence of staples can? make it inadvisable to recycle the container, and furthermore its aesthetic appearance is compromised.

The ultrasonic spot heat-sealing process has the disadvantage of giving the container an unpleasant and inelegant appearance, which becomes particularly limiting in cases where the accuracy of the finishing is of primary importance.

The procedures described above are also? used in applications pi? general, in which the mutual locking of synthetic resin elements is required, and have the same drawbacks described for the containers.

The purpose of the present invention is to propose a method for joining together elements of synthetic resin, such as for example the walls of those portions of a blank, solid or alveolate, which must guarantee stability. of the container which is obtained from this blank in a simple, reliable, functional and pleasant way.

A further purpose of the present invention? that of obtaining, with the proposed method, containers or other objects made up of elements of synthetic resin mutually blocked, which are made exclusively of the same synthetic resin, without adding foreign materials, and therefore easily and advantageously subject to recycling processes.

The above objects are achieved in accordance with the content of the claims.

The characteristics of the present invention are highlighted below with reference to the attached drawing tables, in which:

Figure 1 illustrates a plan view of a blank in a flattened configuration;

- figure 2 shows the section II-II of figure 1;

- figure 3 shows the portions represented in figure 2, during the heat sealing operations;

Figure 4 illustrates a cassette container made starting from the blank of Figure 1;

figures 5 and 6 illustrate the steps of heat sealing the inserts applied to the container of figure 4;

- Figures 7, 8 and 9 illustrate further containers made by applying the method object of the present invention;

Figures 10, 11 and 12 illustrate as many applications of the present method for making corner reinforcements;

- figure 13 illustrates two sheets of synthetic resin mutually blocked by heat sealing at the head; - figure 14 illustrates two synthetic resin plates mutually blocked by overlapping a filler plate.

The present method is described in detail below with particular regard to the application in the production of cassette containers, purely by way of example.

With reference to Figure 1, 1 indicates a flat blank, in its flattened configuration, made with a sheet of synthetic resin, solid or alveolate. In this blank, longitudinal 11,12,13,14 and transverse 15,16 creases are provided, suitable to operate as preferential folding lines, to allow their transformation into a corresponding container 2 of the cassette type (see Figure 4). Blanks having different shape and arrangement of the creases can, for example, give shape to different boxes 3 (figure 4) or box-shaped containers 4,5 (respectively in figures 8 and 9).

The blank 1 also provides longitudinal flaps 17, intended to be folded so as to overlap corresponding walls 18 of the same, and to be fixed thereto to reinforce the structure of the container 2.

A plurality is also applied and fixed to the latter. of inserts 21, designed to define and reinforce the structure of the container 2.

The implementation steps of the method for fixing synthetic resin walls provide for the execution of a succession of operations, which will be described below.

The first of these steps involves folding, with known methods, the blank 1, until it assumes a configuration close to that corresponding to the cassette container 2. Ci? it also includes the partial bending of the longitudinal flaps 17. The inserts 21 are arranged in proximity? of the blank, at a predetermined distance from it.

The first heating means 60 are then approached to the internal facades 17a, 18a of the edges 17 and of the walls 18, adapted to heat the same to a predetermined temperature (Figure 2). Furthermore, second heating means 70, also adapted to heat the aforementioned facades 21a and walls 2a, are approached to the internal faces 21a of the inserts 21 and to the walls 2a of the container 2 (Figure 5).

These heating means 60, 70 are preferably of the type with delivery of hot air, but can equally be of any other type known and used industrially.

The set temperature? such as to cause a superficial melting of the resin in the affected facades.

Once this temperature has been reached, the first 60 and second 70 heating means are moved away, and the facades 17a and 18a are immediately brought together until they mate together. as the faces 21a of the inserts 21 are made to mate with the walls 2a.

At this point, first pressing means 80 are applied from the outside of the flaps 17 and walls 18 (see Figure 3), suitable for exerting opposing stresses on the same opposing stresses, to provide uniform pressure on the facades 17a, 18a and allow them to be heat-sealed. Also applied, outside the inserts 21, second pressure means 90 (figure 6), adapted to exert a uniform pressure on the inserts themselves to allow the heat-sealing of the faces 21a to the walls 2a of the container 2.

The pressing means 80, 90 are removed after a predetermined time, sufficient to allow the previously heated facades to cool beyond the solidification point of the resin.

The heat sealing can? be extended to the entire surface of the aforementioned facades, thus creating an effective watertight seal.

The method described above can? it can also be conveniently applied to blanks having a shape substantially different from that illustrated, for example to those suitable for being transformed into the cassette container 3 or into the box-like containers 4,5 shown respectively in figures 7, 8 and <'> 9. Such blanks usually provide for the presence of flaps to be superimposed and clamped by heat sealing which differ in number, shape and size with respect to the flaps 17 of the blank 1 illustrated. In any case, ? in any case, it is possible to advantageously apply to them the bonding method by heat-sealing described above.

Further applications of the present method are illustrated, by way of example, in Figures 10, 11 and 12. They represent as many modalities. of mutual locking, by heat sealing, of synthetic resin sheets, first 100 and second 101, in a right-angle configuration, with the creation of corner reinforcements 110.

This method can also? be advantageously applied to mutually join the same sheets 100,101 of synthetic resin at the head (figure 13), or by affixing a filler plate 103.

In the first case, the joining method provides for the heating of the heads 100a, l01a of the plates 100,101 up to the melting point of the surface resin. The slabs are then placed side by side and subjected to the action of pressure means, not shown in the figure, which exert stresses in the opposite direction on the heads themselves, so as to keep them together until the cooling and consequent solidification of the surface resin.

In the second case, the internal face 103a of the filler plate 103 and the end portions 104,105 of the plates 100,101 are heated first of all by means of heating means not illustrated, but entirely similar to those previously described. Subsequently, the latter are made to match in correspondence with the respective heads 100a, 10a, and the internal face 103a of the plate 103 is brought into contact with the end portions 104,105. Pressing means are then applied, also in this case not illustrated. of the same type described above, which clamp the aforementioned plates 100,101 to the plate 103, until the resin has cooled, with consequent welding of the previously heated surfaces.

With the application of the method in question, first of all, considerable advantages are obtained in terms of ease of use. and the convenience of recycling the elements of synthetic resin cos? made. There? brings, as a direct consequence, a greater economy? of production of the same, which can be produced starting from lower cost materials. Furthermore, in this way, the aesthetic characteristics of the containers, or of the other elements as well, are significantly improved. made. Furthermore, the uniform and intimate union of the surfaces to be fixed further increases the overall strength of the finished product.

The invention in question? has obviously been described, with reference to the attached drawings, purely by way of non-limiting example, and? therefore it is clear that all those modifications or variations suggested by the practice can be made to it as well as? from its implementation and use, however included in the scope defined by the following claims.

Claims (6)

CLAIMS 1. Method for the mutual fixing by heat sealing of synthetic resin walls of a flat blank 1, intended to be transformed into a corresponding box container 2 by bending along longitudinal creases 11,12,13,14 and transversal 15,16, made in said blank 1, and the subsequent mutual locking of elements of the latter, characterized in that it provides: folding of said flat blank 1 up to a configuration close to that of the corresponding container 2; approaching elements 17, 18 of the latter, in correspondence with respective internal facades 17a, 18a of the same, intended to mutually mate, of first heating means 60, adapted to uniformly heat said inner facades 17a, 18a to a predetermined temperature; mutual juxtaposition of the aforementioned facades 17a, 18a; application, on the outside of said elements 17, 18, of first pressing means 80, for a predetermined period of time, said first pressing means 80 being able to exert a uniform pressure on the aforementioned facades 17a, 18a to allow heat sealing of the same. Method according to claim 1, wherein? the application to said container 2 of a plurality of of inserts 21, external to the same and intended to define and reinforce its structure, characterized by the fact of providing: approach, to the internal faces 21a of said inserts 21 and to walls 2a of the aforementioned container 2, intended to mutually mate, of second heating means 70, adapted to uniformly heat said facades 21a and walls 2a to a predetermined temperature; juxtaposition, up to mutual contact, of said facades 2a to the corresponding walls 2a; application, on the outside of said inserts 21 and inside of said container 2, of second pressure means 90, for a predetermined period of time, such as to allow heat-sealing of the aforementioned facades 21a to the aforementioned walls 2a. 3. Method according to claims 1 and 2, characterized in that the heating of the aforementioned facades 17a, 18a and of the aforementioned facades 21a and 2a of the container 2 is carried out by means of a flow of hot air emitted respectively by the first 60 and second 70 heating means . 4. Method for the mutual fixing of synthetic resin elements, characterized in that it provides for the following sequence of operating phases: juxtaposition, to facades 100a, l01a of synthetic resin elements 100,101 to be joined, of heating means, suitable for bringing the temperature surface of said facades 100a, 101a at a predetermined value, sufficient to cause the surface melting of the synthetic resin; removal of said heating means, and mutual approach of said elements 100, 101 until the aforementioned facades 100a, 101a of the same match; application to the latter of pressing means, suitable for exerting opposing stresses perpendicularly to said facades 100a, 101a, for a predetermined period of time, sufficient to cause heat sealing of the same. 5. Method for the mutual fixing of synthetic resin elements, characterized in that it provides for: the heating of a synthetic resin filler plate 103, in correspondence with its own facade 103a, up to a predetermined temperature, sufficient to cause the melting surface of the resin; the simultaneous heating of end portions 104,105 of the aforementioned elements 100,101 to the same temperature; the approach of said plate 103 to the latter, until said face 103a mates with said end portions 104,105; the application, to the aforementioned elements 100,101 and filler plate 103, of opposing stresses capable of exerting a uniform pressure on them, sufficient to allow them to be heat-sealed. 6. Method for the mutual fixing of synthetic resin elements substantially as described, illustrated and claimed, and for the purposes described above.