Description Process for manufacturing water-soluble containers by thermoforming The invention relates to a process for the manufacture of"water-soluble containers", both of individual containers or also simultaneously of several water-soluble containers with multiple and different filling capacities for example from 1 ml to 10 litres, which containers which may be filled with various kinds of products, such as fluids and/or liquid products, gels and/or liquid products having a high density, powders and/or granular products of various types, paste-type products and/or solid products, and which may in a necessary and sufficient degree be "secure"under the aspect of their resistance against rupture or breakage and/or seepage of the product (s) contained in them, and this until the time of their final use. Namely, the products contained in the water-soluble containers"are released"solely as a result of the dissolution of the packaging material in the presence of water" ; therefore the invention may be utilised and/or applied to most variegated uses and business sectors and product types, such as: detergents and domestic cleaning agents ; deodorants and sanitises; cosmetic and personal hygiene preparations.

In view of the possibility of being able to carry out simultaneous filling of several water-soluble containers at one time, the particular interest of the invention lies in several potential applications thereof, such as the option of: filling all the containers with a single kind of product (product X), filling some with one product (product X') and others with a different product (product Y), filling a same container with different products, at first product X and later on product Y, filling the containers with products of two or more phases (i. e. , product X + product Y), being able to handle simultaneously, in a single filling step, containers different both in shape and in quantity of product contained therein.

The invention moreover permits to apply the process to most variegated kinds of shape, both regular and irregular, as well as the realisation of shapes encompassing: objects of common and/or daily use, such as flasks and/or bottles, cups and various containers, tubes and cans or jars, boxes/packages, etc. objects and/or shapes demanded in aesthetic terms by marks and/or products of the market.

Figs. 1 to 8 show the four respective views of several exemplary containers.

At present, there is a large number of patents capable in some manner of addressing the topic of the production of

"containers of water-soluble materials", either in order to define aspects of productivity and workability, or also attempting to resolve aspects of a particular use and/or of the diversification of their industrialisation and/or their manufacturing process: from among those, it is certainly possible to mention, for instance, the following: WO 92/17382-WO 93/08095-WO 00/55068-WO 00/55415- WO 02/16207-etc.

In contrast with anything that has already been addressed by the prior art, the present invention does not have the single objective of realising"containers of water- soluble material", but rather has a broader and twofold objective, i. e. : a) a diversified handling and thus an improvement of the actual problems of thermoforming materials of the water-soluble type which, given their peculiarity, pose difficulties of treatment and stability and therefore require particular attention in their handling, not only during production, but also during their subsequent confectioning and storage; b) but also to obtain, in the scope of a single thermoforming process, the"simultaneous"creation of the "water- soluble container"and of a practical and exclusive system of a"flat base and dome-shaped body"of semi- rigid and/or rigid and/or semi-flexible material, either of the"nonpeelable"or"peelable"type and which, as

it assumes precisely the same shapes of the water- soluble container, in turn is conceivable as: a primary container for the protection of the water- soluble containers, an element both for packaging and decorative purposes, an element facilitating practicability of use by the final consumer, an element facilitating apportioning of the products through the predisposition of predetermined single doses.

The invention consists in having resolved, in a single processing step, several of the more critical aspects of such water-soluble containers, such as on the one hand the need for an even better protection (given their inherent fragility), on the other hand facilitation of the packaging process, and consequently the resulting and quite considerable optimisation of confectioning costs.

The invention allows to obtain the following improvements: both through the"formation of the pouch, formation of the container, filling and closing of the water- soluble container", all in a single production process, and through the use of three (3) materials (designated in Fig. 9 by"B1","B2","B3") : these materials have the characteristic of both"B2"and"B3"being materials of the water-soluble type and therefore "compatible for welding"among each other, whereas "B1"is"not compatible for welding"with the other two.

Fig. 9 is a schematic view which illustrates by way of example the process of manufacturing water-soluble containers according to the invention.

The main characteristic of the invention consists in the combined use of three different materials in the form of rolls, but above all the obligatory use of two of these ("Bl"and"B2") in combination for thermoforming the pouch which then is intended for filling with the product.

Products B1 and B2 may also in advance be compounded in a single roll.

These materials are supplied in the form of rolls, the dimensions of which depend on the machine on which they are to be utilised, and are materials which may be procured on the market without any limitations, and which are utilised for various uses. The materials in the form of rolls are those described in the following: Material'B1"preferably is a polypropylene/polyethylene compound material, however it may also be another kind of material and compounded (in 2,3, or more layers) which may furthermore be used in the process, such as polyester, PVC, polyester/polyethylene, polyester/polypropylene, metallised polypropylene, etc.

Material"B2"is a material preferably of PVAL (polyvinyl alcohol), and thus a material which is soluble upon

contact with water; also other kinds of materials, which are also soluble in water, may be used in the process; moreover in accordance with the final uses it is possible to utilise materials that are soluble in water but also compounded with other materials which do not permit "peeling", such as cardboard, aluminium, plastics, etc.

Material"B3"is, just like in the case of"B2", a material preferably of PVAL (polyvinyl alcohol), and therefore soluble upon contact with water; also other kinds of materials, which are also soluble in water, may be used in the process; moreover in accordance with the final uses it is possible to utilise materials which are soluble in water but also compounded with other materials that do not permit"peeling", such as cardboard, aluminium, plastics, etc.

The process for producing the containers takes place with the aid of a horizontal-type method of conveying the materials, where the sequence of the single processing steps is the following: a) uncoiling the first two (2) different materials,"Bl"and"B2" : these are or are not compounded with each other, but are wound and transported simultaneously, one superposed on the other, and are both simultaneously involved in the step of thermoforming the containers.

Material"B1"is used as a first layer and thus in direct contact with the"female"moulding die; when the processing is concluded, this material constitutes the above described"dome-shaped body structure"that is not soluble in water and thus has a function of containing the actual water-soluble container.

Material"B2", on the other hand, which is of water- soluble PVAL, constitutes the lower part of the water- soluble container; in the thermoforming process it enters into contact with the"male"mould and then enters into direct contact with the product for filling. b) Both materials"B1"and"B2"are initially pre- heated until the temperature suitable for forming is attained, which temperature may vary, both owing to the kinds and the thicknesses of the used materials, through a temperature range which may span from a minimum of 90° to a maximum of 280° (cf. 1 in Fig. 9); c) these are then positioned above the mould having one or more cavities; d) there, during a moulding process of the"male + female die"type, they are thermoformed in the mould, so that they may perfectly line the walls and the bottom of the single cavity of the mould (cf. 2 in Fig. 9) e) correspondingly, during the thermoforming process,"B1"and"B2"adapt simultaneously and perfectly to

the"female"mould so as to assume and maintain their shapes: the true peculiarity of these two products is that, notwithstanding the thermoforming process, and notwithstanding the variations of the thermoforming temperature, the two materials are compounded to each other"while not welded together permanently", inasmuch as they are materials which are incompatible with each other. As a result, this process allows to obtain not a single but two (2) concentric pouches that are perfectly and coaxially superposed on each other, and despite this always easily separable from each other; the first one (of material"Bl") then forms the "dome-shaped body structure", with the second one (of material"B2") forming the lower part of the actual water-soluble container, which then is successively filled with the product (s); f) the thus-obtained pouches advance by being conveyed to the subsequent step, where those formed of material "B2"are filled with the product (s) (cf. 3 in Fig.

9); g) still by conveying, the pouches advance to the closing step which takes place through hot welding between the two (2) materials 8WB2WW and"B3"; this closing takes place by paying out the third roll-type material which equally consists of water-soluble PVAL ("B3") which, when superposed on the two previous materials which are already thermoformed and filled, thus completes the manufacture of the water-soluble container, which then is already inserted in a"flat base and/or container dome portion"thereof, of identical shape and

dimensions (cf. 4 in Fig. 9); h) the following step provides the"cutting" (cf.

6 in Fig. 9) with the aid of a suitable predisposed punching tool for the purpose of obtaining three different objectives: first of all, to separate the finished product from excess material and from the wastes which, in their turn, are rewound on a roll intended for receiving them; through particular adjustments of the punching tool, to obtain a pre-cutting perforation between each individual imprint and the ones adjacent thereto, so as to permit easier separation into single doses (cf. 5 in Fig. 9); moreover, this particular perforation has the further purpose of acting as an element for facilitating maintaining contact between material"Bl"and the water-soluble container (i. e. , the two materials"B2"and "B3"welded to each other) until the time of use of this water-soluble container; i) from the above described process (cf. Figs. 10 and 11) various"series of water-soluble containers"are output, all of which are already prepared in their "flat base and dome-shaped body"and thus ready for packaging a plurality thereof in boxes.