EP0723920A1 - Temporary container for printing ink - Google Patents

Abstract

The container, e.g. for ink used in copper-plate engraving, consists of an outer package (10) of a rigid material, in the shape of a right prism, and an inner package (24) of a flexible material in the form of a back which can be hermetically sealed. The outer package is of cardboard, and preferably corrugated cardboard, and has an octagonal cross-section formed by a square with cut-away corners. It is designed to be carried on a standard European pallet or a sub-division of it, having a width or length of 80 cm. The inner package is made from two lengths of a flexible material, joined by adhesive or welding along their long edges. The flexible material is composite and synthetic, comprising a layer which is impermeable to gas and preferably also to light. It has an inner layer of a polyolefin 70 to 100 mcm thick, an intermediate layer of aluminium 9-12 mcm thick, and an outer polyester layer of 8-15 mcm thick. The inner polyolefin layer can be, for example, of polyethylene, and polyurethane can be used in place of polyester for the outer one.

Description

The present invention belongs to the field of printing inks. More particularly, it refers to a temporary container or container which can contain a predetermined quantity of ink, this container being transportable and disposable and the materials of which can be destroyed or recovered, respectively.

Until now, printing inks, in particular intaglio printing inks in the form of an extremely viscous and thixotropic paste, have been transported from the ink manufacturer to the user in cans, usually steel, containing about 25 kg of ink. These canisters are heavy by themselves, they are expensive, and they also occupy a lot of space on the transport pallets; the result is that a pallet shipment has a poor relationship between the volume and the weight of the load. In addition, the volume of air remaining in the container creates the risk that a skin will form on the surface of the ink.

There is no question of emptying the contents of the container into the printer's ink tanks by flow because the paste is too viscous; a tray must be placed with a hole in the middle on the surface of the ink contained in the container, the tray is pressurized, and a reciprocating pump sucks the ink through the hole in the tray. Since the container must be pressurized, light containers cannot be used; it is necessary that the container withstands the pressure. In addition, it is very painful to clean the container after emptying - which always leaves a significant amount of ink which can be about 500 g in the container -, and this cleaning requires a lot of time and solvent or other cleaning product. It is out of the question to throw away the container after emptying.

The object of the present invention is to create a temporary packaging for the transport of printing inks, in particular but not exclusively, intaglio inks, which eliminates all the disadvantages listed above. This object is achieved by the temporary container according to the invention which is defined in independent claim 1, special executions which are the subject of the dependent claims.

The container of the invention consists of two parts, namely an outer packaging and an inner packaging. The inner packaging is flexible, preferably hermetically sealed and impermeable to gases and light, and made from a sheet of synthetic material. The outer packaging supports the weight of the ink that is contained in the inner packaging; it is a straight prism, that is to say a solid body (which is naturally hollow to form the container) having two equal and parallel polygonal bases, the lateral edges of the body being perpendicular to the bases. The bases can be square, pentagonal, hexagonal, octagonal etc .; for the reasons which will be explained below, an octagonal base with equal angles is preferred, the opposite sides of which have the same length; they are not necessarily regular octagons; on the contrary, a certain non-regular form of the octagon is preferred, which will be described below.

The outer packaging is preferably made of cardboard, especially corrugated cardboard, although any other solid and resistant material can be used, for example reinforced plastics, such as those made from plastic waste. This outer packaging contains the inner packaging which is preferably a tube made of a flexible composite sheet, closed by folding and heat sealing and, once filled with printing ink, closed in the same way at the top, but this time under vacuum. The composite sheet preferably comprises a layer of polyethylene or any other polyolefin inside, coming into contact with the ink, this layer naturally having to be inert with respect to the ink. Then, this inner layer is covered with a sheet impermeable to gases, in particular to oxygen and water vapor, to light and, all the more so, to all liquids. Generally, metals such as aluminum are used for this layer, but it is in principle also possible to use highly pigmented plastics, for example carbon black. Finally, an outer layer was provided in this composite sheet; this outer layer protects the aluminum foil and is made of polyester or any other flexible and resistant material such as polyurethanes. If protection against light is not necessary, the intermediate layer described can be omitted.

As regards the thicknesses, the internal layer has a thickness of between 70 and 100 μm, the intermediate layer, preferably of aluminum, between 9 and 12 μm, and the outer layer between 8 and 15 μm.

The outer packaging has a polygonal section. An object of the present invention was to create a packaging which takes up the least space on a well-known transport pallet and is used all over the world, especially in Europe where its dimensions are standardized; these pallets have a loading surface of 80 cm by 120 cm. This aim which has just been defined must however take into consideration the fact that an inner packaging, normally of circular section, must be placed in the outer packaging. However, space on a pallet is best used by square packaging; but in these square packages, a circular bag is difficult to insert, and despite its flexibility, it adapts very little to the interior walls of the package which may also burst because it contains empty volumes, not occupied by the bag containing the ink. On the other hand, an outer packaging circular section, so a drum, would be best suited to the bag that forms the inner packaging but a lot of space would be lost not only on pallets but also in warehouses.

It has therefore been found, according to an important aspect of the invention, that an octagonal prism shape has many advantages although any other polygonal shape is also usable. The octagonal shape is a good compromise between the circular shape and the square shape. We can use a regular octagon but, in order to better use the space on a pallet, we have found that a special octagon is particularly advantageous; it is a square whose angles are cut in such a way that the new edges thus formed are shorter than the remaining sides which come from the primitive square. In other words, two orthogonal pairs of edges of a regular octagon were pushed outward.

environ et un second côté de $\text{2 * 3,4 = 6,8 cm}$

environ. Ces mesures sont assez approximatives vu les tolérances de fabrication des articles en carton ondulé. Les angles entre les côtés sont égaux et ont la valeur de celle de l'octogone régulier, à savoir 135°.For example, if we look at the width of the standard pallet which is 80 cm, or the length of a subdivided pallet which is also 80 cm, we divided this measurement by three to obtain approximately 26 cm. This dimension is that of the primitive square. Then, since the tank intended to receive the inner packaging has a diameter of 30 cm, the four corners of the square are cut so as to obtain a new diagonal of 30 cm, the original diagonal being approximately 36.8 cm, so we cut twice 3.4 cm on the diagonal. The octagon thus formed therefore alternately comprises a first side of $\text{(26 - 2 * 4.8) = 16.4 cm}$

about and a second side of $\text{2 * 3.4 = 6.8cm}$

about. These measures are fairly approximate given the manufacturing tolerances of corrugated articles. The angles between the sides are equal and have the value of that of the regular octagon, namely 135 °.

As a general rule, the ratio between the first and second sides should be between 2: 1 and 5: 1, preferably between 2: 1 and 3: 1, and more preferably still amounts to about 2.4: 1.

et $$\text{b/d = √2*x /(1-2*x) ≦ 0.556;}$$

où:

x=

la fraction totale decoupée de la diagonale du carré primitif;

b=

la largeur des seconds côtés 36 a/b,

d=

la largeur des premiers côtés 34 a/b.

With regard to the space sacrificed for cutting the corners of the primitive square, a suitable limitation for this space is Q ≦ 10% of the area of the primitive square. After a simple calculation, we arrive at the following two relationships: $$\text{x = √ (Q / 2) ≦ 0.22}$$

and $$\text{b / d = √2 * x / (1-2 * x) ≦ 0.556;}$$

or:

x =

the total fraction cut from the diagonal of the primitive square;

b =

the width of the second sides 36 a / b,

d =

the width of the first sides 34 a / b.

If the quotient b / d is between 1: 2 and 1: 5, as mentioned above, then x is between approximately 0.21 and 0.11, and Q between approximately 0.088 and 0.024.

It has been found, surprisingly, that the crushing resistance of such a package is much greater than that of a square package and essentially equal to that of a circular package, the dimensions being chosen to be comparable. It is especially the vertical edges which are reinforced, which ensures stacking of the containers.

To fill the container according to the invention, it is first possible to place the inner packaging, closed at the bottom by heat-sealing or heat-sealing, in the outer packaging and then fill the container. Then, the inner packaging is closed in the same way, this time under vacuum, and the outer packaging is also closed by folding and sticking the closure tabs. But you can also fill and close the inner packaging first and then slide it in, using a short conical tube with an appropriate diameter, in the outer packaging.

To empty the container according to the invention, two methods can be used, the choice of which depends on the use:

progressive (slow) for ready-to-use inks that feed a printing machine; or
fast for basic inks intended for the production of fine tint inks.

In the first case, the emptying is done by a suction pump comprising a thrust plate and the action of a reciprocating piston; this device is known. The bag is removed from its carton by tearing the carton using a tab provided for this purpose in the lower half of the carton, and the bag is placed in a solid cylindrical container of stainless steel, specially studied and having a corresponding internal diameter the diameter of the bag. We make a circular opening on the top of the bag. The pump plate comes to rest on the bag from the top and forces it to press against the wall of the container, and then the piston begins its action of extraction of the ink by suction. The bag gradually crashes. At the end, it is collected from the bottom of the container in the form of a thin cake containing another 250 g to 500 g of ink.

In the second case, the cardboard is opened in the same way, by prepared tearing of the cardboard and the bag is placed in a solid cylindrical container specifically studied, having a central circular hole at the bottom and a circular disc pierced with a circular hole also , but of smaller diameter over it. The container with the bag in it is put on a press, then the bag is drilled at the bottom through the hole in the disc. Then the press plate exerts a strong pressure on the bag and pushes the ink to come out from the bottom and fall into a tank placed below the hurry. The circular hole of the disc which is smaller than that of the container ensures that the container does not get dirty. One can also provide several interchangeable discs having holes of different diameters depending on the fluidity of the ink to be extracted. When you do not want to empty the bag completely, you can leave it in the container with the hole and close the hole with a suitable plug, for example a plastic cover as used for cardboard tubes.

La fig. 1

montre une vue en perspective d'un récipient préféré;

la fig. 2

est une vue en perspective de l'emballage intérieur encore contenu dans l'emballage extérieur qui a été déchiré et retiré en partie;

la fig. 3

est une vue de dessus de l'emballage extérieur du récipient;

la fig. 4

montre le remplissage du récipient; et

la fig. 5

montre la fermeture du récipient.

In the drawing, there is shown an embodiment of the container according to the invention:

Fig. 1

shows a perspective view of a preferred container;

fig. 2

is a perspective view of the inner packaging still contained in the outer packaging which has been torn and partially removed;

fig. 3

is a top view of the outer packaging of the container;

fig. 4

shows the filling of the container; and

fig. 5

shows the closure of the container.

We can see in fig. 1 the body 10 of the outer packaging of the container according to the invention. This packaging is made of corrugated cardboard and made in a known manner from a flat pattern. The pattern is folded and then glued along the edge 12. The tear-off tab 14 ends in this edge 12. Upwards, the packaging is closed by four glued flaps of which only the two upper flaps 16, 18 are seen. In addition, the corrugated cardboard packaging 10 has tabs 20 forming, when pushed in, gripping openings, the tabs being stamped in the carton and partially perforated so that they remain attached to the body 10.

Fig. 2 shows the inner packaging 24, namely a bag made of a composite sheet as described above. The bag can be an extruded tube or pipe with circular section; in the present example, it is obtained by gluing two lengths of superimposed composite sheet along their edges, and it is closed at the top by laying the tube flat and gluing the sheet together, thus forming a closure strip 26. The bag 24 is still standing in the torn lower part 22 of the outer packaging 10.

Finally, fig. 3, which is a schematic view from above of the container according to the present example, shows the original (fictitious) square 30 which served as the basis for drawing the octagon 32. This octagon comprises two pairs of long edges 34a, 34b , opposite by the center, and two pairs of short edges 36a, 36b, also opposite by the center. The linear dimension 38 is that which determines the size of the container, for example on a pallet, and the linear dimension 40 is the distance from the opposite short edges 36a, 36b which determines the capacity of the inner packaging 24. The latter is symbolized by the dotted outline 42. It can be seen that the inner packaging adapts well to the internal walls of the outer packaging.

The wafer that forms after emptying the bag and crushing it, can be subjected to ink and aluminum recovery treatments at least. The outer packaging 10 can be burnt without leaving harmful or otherwise dangerous residues, for example in waste incineration plants. It can also be recycled.

In this way, the invention has the additional advantage that the new temporary container is non-polluting and respects the environment. This container is advantageously applicable for units for making ink from 10 kg to 100 kg, and more specifically for conventional 25 kg units.

The container is filled so that no air pocket forms between the ink and the wall of the bag. Because it is known that inks based on vegetable oil form a skin in contact with oxygen in the air. Air pockets are prevented by a mechanical filling method, automatically controlled by a computer, which maintains an almost constant distance, throughout the operation, between the ink surface and the filling nozzle.

In addition, intaglio printing inks, for which the packages according to the invention have been specially designed, have a high viscosity, for example more than 3 Pa s at 40 ° C, and often more than 7 Pa s . Therefore, these inks cannot be poured as liquids and only fill a space such as packaging very slowly, which is unacceptable for an industrial process. This problem is also solved by this mechanical filling method.

A preferred installation for implementing this filling process according to FIGS. 4 and 5 essentially consists of a support 51 for the packaging 50 and a nozzle 53. At the orifice 55 of the nozzle 53 is a valve 54 provided inside with movable blades 56. The blades 56 serve to close the orifice 55 and shown in the open state. The ink 57 flows under pressure through the nozzle 53 and is added to the ink 58 already arrived in the packaging 50.

By a movement of the nozzle 53 and / or of the support 51 controlled by the computer, the distance between the orifice 55 and the surface of the ink 58 in the package 50 is kept constant throughout the filling. Likewise, a flat, that is to say minimal, surface of ink 58 is obtained, as well as close contact with the bag 24 and the outer packaging 10.

To avoid the formation of skins during storage of the filled packages, the bag 24 is sealed under vacuum. The best way is to heat-seal the bag. A good quality seal is only obtained if the surfaces of the bag remain free of traces of ink. To ensure excellent maintenance of the cleanliness of the bag in the area to be welded, suitable methods and equipment have been developed. It is well known that inks based on resin and vegetable oils easily form threads which soil the tools and equipment used to handle them. Also, the valve 54 includes a suitable closing mechanism and equipped with a very effective wire cutter which ensures that the bag is not stained with ink upon arrival and departure from its filling position under the nozzle. , along a filling chain. According to fig. 4, the orifice 55 is closed by inserting the blades 56. In other words, the valve 54 cuts the wire in the manner of a sphincter which widens to let a fluid pass and which closes when the flow is stopped.

Likewise, the vacuum has been designed to be very fast. By this speed, the ink which could flow under the effect of atmospheric pressure and be placed in the area of the bag which must be welded, does not have time to move before a sufficient vacuum of air n 'has been obtained and soldering has been carried out.

Fig. 5 shows the condition fulfilled and evacuated the packaging after the air has been rapidly sucked in via the vacuum duct 60. Since the ink has not deformed due to its viscosity, the inner bag 24 of the packaging matches the almost solid ink mass 58. Above the ink 58, the bag closed well under atmospheric pressure and thus formed the probing zone 62.

The filling method and devices are only preferred examples, and the specialist can develop modifications without departing from the scope of the invention.

Claims (14)

Temporary container for printing inks, in particular for intaglio printing inks, characterized in that it is composed of an outer packaging (10) of rigid material having the shape of a straight prism, and d an inner packaging (24) of flexible material in the form of a bag which can be hermetically sealed. Container according to claim 1, characterized in that the outer packaging (10) is made of cardboard, preferably corrugated cardboard, and of octagonal cross section. Container according to claim 2, characterized in that this octagonal section is formed by a square (30) whose four angles are cut at 45 °, the width of the second sides (36a, 36b) thus formed being smaller than the width the first sides (34a, 34b) remaining of the original square (30). Container according to claim 3, characterized in that the ratio between the width of the first sides (34a, 34b) and the width of the second sides (36a, 36b) is between 2: 1 and 5: 1, preferably between 2: 1 and 3: 1, more preferably about 2.4: 1. Container according to claim 3 or 4, characterized in that the distance between two opposite second sides is at a fraction of the diagonal of the square (30) equal to or greater than 0.78, this fraction preferably lying in a range from 0.78 to 0.90 . Container according to one of Claims 2 to 5, characterized in that it is adapted to be transported on a standard European pallet or a subdivision of such a pallet, having a width or length dimension, respectively, of 80 cm, the sides of said square pitch having a length of about 26 cm and the distance between the opposite sides of a pair of second sides (36a, 36b), formed by cutting the pitch square, being about 30 cm. Container according to any one of the preceding claims, characterized in that the inner packaging consists of a bag formed by two superimposed lengths of a flexible sheet, joined by gluing or welding the longitudinal edges. Container according to one of Claims 1 to 7, characterized in that the material of the inner packaging (24) is a composite sheet of synthetic material containing a layer which is impermeable to gases and preferably also to light and that the composite sheet consists of an inner polyolefin layer, between 70 and 100 µm thick, an aluminum intermediate sheet between 9 and 12 µm thick, and an outer polyester layer between 8 and 15 µm. Container according to any one of claims 2 to 8, characterized in that the outer packaging (10) of corrugated cardboard is equipped with a tear-off tab (14) having a peripheral gripping tab and located in the lower half of the prism which constitutes the packaging. Container according to any one of the preceding claims, characterized in that it is filled with printing ink, in particular intaglio printing ink. Container according to one of claims 1 to 10, characterized in that the inner packaging is closed by heat sealing or vacuum fusing. Method of filling the container according to one of claims 1 to 11, characterized in that the ink is introduced under pressure by a nozzle (53), and that the distance from the orifice (55) of the nozzle (53) is kept more or less constant throughout the filling procedure. Method according to claim 12, characterized in that to complete the filling, the orifice (55) is closed by a valve (53) arranged close to the orifice (55) and comprising a closing means acting in the manner of a wire cutter. Method of filling the container according to one of Claims 1 to 11 or according to Claims 12 or 13, characterized in that after the filling of the container (50), the container is evacuated fairly quickly, so that the ink does not deform appreciably during this time, so that the inner packaging (24) follows the mass of the ink (58) and closes above the ink (58) by creating a free zone (26) d ink and can be welded.

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